300. At the outset, the Appeals Chamber recalls that Article 49 of Geneva Convention IV applies to instances of displacement across the de facto borders of an occupied territory.[1] In the Stakić case, the Appeals Chamber held that “the actus reus of deportation is the forced displacement of persons by expulsion or other forms of coercion from the area in which they are lawfully present, across a de jure state border or, in certain circumstances, a de facto border, without grounds permitted under international law”.[2]

301. The Appeals Chamber considers, therefore, that the Trial Chamber properly examined whether a state of occupation existed in those places in relation to which the Indictment raised allegations of deportation as a grave breach of the Geneva Conventions, i.e. in West Mostar and the municipalities of Prozor, Ljubuški, Stolac, and Čapljina.[3] That inquiry involved an element of the crime of deportation itself – the crossing of a de facto border, i.e. the boundary of the occupied territory, or across a de jure border – which was separate and distinct from the general requirements for the application of the “grave breaches” regime under Article 2 of the Statute.

316. Belligerent occupation[1] forms part of the law of armed conflict. As the ICJ held with respect to Geneva Convention IV in its Advisory Opinion on the Wall [Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, 9 July 2004]:

The object of the second paragraph of Article 2[2] is […] directed simply to making it clear that, even if occupation effected during the conflict met no armed resistance, the Convention is still applicable. This interpretation reflects the intention of the drafters of the Fourth Geneva Convention to protect civilians who find themselves, in whatever way, in the hands of the occupying Power […] [T]he Court considers that the Fourth Geneva Convention is applicable in any occupied territory in the event of an armed conflict arising between two or more High Contracting Parties.[3]

317. The Appeals Chamber notes that a definition of occupation can be found in the Hague Regulations, which constitute customary international law.[4] Article 42 of the Hague Regulations provides that “[t]erritory is considered occupied when it is actually placed under the authority of the hostile army. The occupation extends only to the territory where such authority has been established and can be exercised.”[5] The Appeals Chamber considers this to be the controlling law.[6]

318. The notion of occupation is traditionally described as one State invading another State and establishing military control over part or all of its territory.[7] However, while occupation normally follows invasion by a hostile armed force, this is not necessarily always the case.[8] Indeed, the ICJ has held that a non-invading State became an occupying power when its armed forces remained in another State’s territory after the withdrawal of consent for their presence.[9]

319. The Appeals Chamber further notes that occupation is a question of fact and needs to be examined on a case-by-case basis.[10] Vagaries of war and the changing situation on the ground may influence the parameters of the territory under occupation.[11] The fact that a territory is occupied does not exclude the possibility that hostilities may resume.[12] If the occupying power continues to maintain control of the territory in spite of resistance and sporadic fighting, the territory is still considered occupied.[13]                                                                                                                                                                                   

320. In this regard, the Appeals Chamber considers that the following indicators of authority, as first outlined in the Naletilić and Martinović Trial Judgement (“Occupation Guidelines”), assist in the factual determination of whether the authority of an occupying power has been proven:

(1)     the occupying power must be in a position to substitute its own authority for that of the occupied power, rendered incapable of functioning publicly from that time forward;[14]

(2)    the enemy’s forces have surrendered, been defeated or have withdrawn. In this respect, battle zones may not be considered as occupied territory. Despite this, the status of occupied territory remains unchallenged by sporadic local resistance, however successful;[15]

(3)    the occupying power has a sufficient force present, or the capacity to send troops within a reasonable time to make the authority of the occupying power felt;[16]

(4)    a temporary administration has been established over the territory;[17]

(5)    the occupying power has issued and enforced directions to the civilian population.[18]

321. The Appeals Chamber considers that in order to make a finding as to whether a state of occupation exists in any given place, a trier of fact must look at the situation in its entirety.[19] The Appeals Chamber further considers the Occupation Guidelines to form a non-exhaustive set of indicators that can assist in this factual determination of whether actual authority has been established and can be exercised for the purposes of occupation.[20]

322. The Appeals Chamber also considers that the occupying power need only be in a position to exercise its authority.[21] This is supported by a plain reading of the relevant article of the Hague Regulations, which states in part that “[t]he occupation extends only to the territory where such authority has been established and can be exercised”.[22] Such authority may be exercised by proxy through de facto organised and hierarchically structured groups.[23] The rationale behind this is that States should not be allowed to evade their obligations under the law of occupation through the use of proxies.[24] This legal position has been implicitly accepted by the ICJ and it is the position taken by this Tribunal in a number of trial judgements.[25]

              […]

335. [T]he Appeals Chamber notes that a state of occupation and that of an international armed conflict are not necessarily mutually exclusive.[26] Further, [T]he Appeals Chamber recalls that a finding of active hostilities in certain municipalities does not necessarily preclude the Trial Chamber from finding that a state of occupation existed on the ground in those municipalities. The Appeals Chamber considers that the issue is one of authority, i.e. whether the occupying power is able to maintain its authority over the territory in spite of some ongoing active combat.[27]

              […]

339. [T]he Appeals Chamber recalls its statement of the law above, and holds that invasion is not a prerequisite for the determination of a state of occupation.[28] […] Moreover, […] the Appeals Chamber highlights that the Trial Chamber established when occupation started in each relevant town and village in each affected municipality.[29] The Appeals Chamber also considers that the Trial Chamber properly found that occupation can be established, once combat ceases, if the occupying power has the required control.[30]

            […]

341. Lastly, with regard to the argument that the principle of self-determination of peoples negates any finding that the HVO [Croatian Defence Council (Army of BiH Croats)] occupied territory in BiH because Croats had been living in the territory of HZ(R) H-B [Croatian Community and Republic of Herceg-Bosna] for centuries, the Appeals Chamber considers that this is not inconsistent with the Trial Chamber’s finding that the HVO occupied territory in BiH as an agent of Croatia.[31] This is because the test for occupation is actual authority over the territory and population and not the motivation behind such an occupation. The Appeals Chamber thus rejects this argument.

Footnote 973: See Naletilić and Martinović Trial Judgement, para. 217 & fn. 585, referring to 1958 UK Manual on the Law of War, paras 502 (“Occupation must be actual and effective, that is, there must be more than a mere declaration or proclamation that possession has been taken, or that there is the intention to take possession. Occupation does not take effect merely because the main forces of the county have been defeated. On the other hand, to occupy a district it is not necessary to keep troops permanently stationed in every isolated house, village, or town. It is sufficient that the national forces should not be in possession, that the inhabitants have been disarmed, that measures have been taken to protect life and property and to secure order, and that, if necessary, troops can within a reasonable time be sent to make the authority of the occupying army felt. It does not matter by what means in what ways the authority is exercised, whether by military enclaves or mobile columns, by large or by small. The manner of occupation will usually vary with the density of the population-a thinly populated country requiring, as a rule, a smaller number of centries to be garrisoned than the one which is thickly populated. The fact that there is a defended place or zone still in possession of the national forces within an occupied district does not make the occupation of the remainder invalid, provided that such place or defended zone is surrounded and effectively cut off from the rest of the occupied district”), 506 (“The test of the commencement of occupation is the establishment of the Occupant’s authority by the presence of sufficient force following on the cessation of local resistance, in consequence of the surrender, defeat, or withdrawal of the enemy’s forces, and the submission of the inhabitants. In practice the moment may be difficult to determine, and considerable latitude must therefore be allowed”), 509 (“Occupation does not become invalid because some of the inhabitants are in a state of rebellion, or through occasional successes of guerrilla bands or ‘resistance’ fighters. Even a temporarily successful rebellion is not sufficient to interrupt or terminate occupation, provided that the authority of the legitimate government is not effectively re-established and that the Occupant suppresses the rebellion at once. If, however, the power of the Occupant is effectively displaced for any length of time, his position vis-à-vis the inhabitants is the same as before the occupation”); 1956 US Manual on the Law of War, paras 356 (“It follows from the definition that belligerent occupation must be both actual and effective, that is, the organized resistance must have been overcome and the force in possession must have taken measures to establish its authority. It is sufficient that the occupying force can, within a reasonable time, send detachments of troops to make its authority felt within the occupied district. It is immaterial whether the authority of the occupant is maintained by fixed garrisons or flying columns, whether by small or large forces, so long as the occupation is effective. The number of troops necessary to maintain effective occupation will depend on various considerations such as the disposition of the inhabitants, the number and density of the population, the nature of the terrain, and similar factors. The mere existence of a fort or defended area within the occupied district, provided the fort or defended area is under attack, does not render the occupation of the remainder of the district ineffective. Similarly, the mere existence of local resistance groups does not render the occupation ineffective”), 360 (“Occupation, to be effective, must be maintained. In case the occupant evacuates the district or is driven out by the enemy, the occupation ceases. It does not cease, however, if the occupant, after establishing its authority, moves forward against the enemy, leaving a smaller force to administer the affairs of the district. Nor does the existence of a rebellion or the activity of guerrilla or para-military units of itself cause the occupation to cease, provided the occupant could at any time it desired assume physical control of any part of the territory. If, however, the power of the occupant is effectively displaced for any length of time, its position towards the inhabitants is the same as before occupation”); 1992 German Manual on the Law of War, para. 528 (“Occupied territory does not include battle areas, i.e. areas which are still embattled and not subject to permanent occupation authority (area of invasion, withdrawal area). The general rules of international humanitarian law shall be applicable here.”), New Zealand Defence Force, 26 Nov 1992, paras 1302.2, 1302.5.