Azerbaijan v. Armenia

Case summary

At a glance

Parties: Republic of Azerbaijan v. Republic of Armenia
Case no.: PCA Case No. 2023-60
Forum and rules: Inter-State arbitration under Article 18 of the Bern Convention, administered by the PCA as Registry; Rules of Procedure adopted by the Tribunal (Procedural Order No. 1, 29 March 2024)
Treaty: Convention on the Conservation of European Wildlife and Natural Habitats of 19 September 1979 (Bern Convention)
Tribunal: Dr. Václav Mikulka (Presiding Arbitrator), Judge Bruno Simma, Judge Nicolas Michel
Sector: Environment; wildlife and habitat conservation
Outcome: Decision on Bifurcation (23 December 2025): Armenia's Article 18 objections are to be heard in a preliminary phase and the merits are suspended. Its other objections are joined to the merits. The published documents do not show a decision on jurisdiction or the merits.
Amount: Azerbaijan seeks monetary compensation for full reparation, to be quantified during the proceeding, plus costs and interest. No amount is stated in the documents.

The dispute

Azerbaijan began this inter-State arbitration against Armenia on 18 January 2023 under Article 18(2) of the Bern Convention. It alleges breaches of Articles 2, 3, 4, 5, 6, 7, 10 and 11 of the Convention; its Statement of Claim no longer seeks relief under Articles 5 and 10. The claims concern harm to species and habitats in the "Affected Area": Xankəndi city and districts of the Garabagh and Eastern Zangezur economic regions. Azerbaijan argues that Armenia exercised effective control and jurisdiction there. It also claims transboundary pollution of the Okhchuchay (Voghji) River from mining facilities in Armenia. Armenia raised seven objections to jurisdiction: - Azerbaijan did not refer the matter to the Bern Convention Standing Committee and did not genuinely negotiate first (Article 18). - The Convention's obligations do not apply outside Armenia's sovereign territory. - In the alternative, the law of armed conflict, not the Convention, governs the Affected Area claims. - The conduct alleged cannot breach Articles 4(4) and 11(1)(a). - Azerbaijan has not made a prima facie case on attribution.

Key holdings

Under Article 14(4) of the Rules of Procedure, preliminary objections are heard separately by default. That rule gives way where an objection lacks an exclusively preliminary character, or where other factors, guided by the Tribunal's duty of fairness and efficiency under Article 9(2), justify joining it to the merits. The Tribunal did not decide whether the 'seriousness' of an objection is a relevant factor. Decision on Bifurcation ¶¶ 89–97
The Article 18 objections (the Standing Committee and Negotiations Objections) are exclusively preliminary. They turn on the meaning of Article 18 and on facts separate from the merits. Because these are the first arbitral proceedings under the Convention, the questions are new and deserve proper consideration. If upheld, the objections could dispose of the whole case. They are therefore to be heard in a preliminary phase. Decision on Bifurcation ¶¶ 99–107
The Territorial Objection is not exclusively preliminary. To decide the territorial scope of Articles 2, 3, 4, 6 and 7, the Tribunal may need to determine the substantive content of those same obligations and the nature of any control Armenia had over the Area, which are disputed facts. The transboundary claims, which the objection does not affect, rest on the same obligations. The objection is joined to the merits. Decision on Bifurcation ¶¶ 108–115
The Law-of-Armed-Conflict Objection lacks an exclusively preliminary character. To decide whether occupation is the 'real issue in dispute', the Tribunal would have to settle the relationship between the law of armed conflict and the Bern Convention, and that analysis overlaps heavily with the merits. The objection is also only an alternative to the Territorial Objection, which has been joined to the merits. It too is joined. Decision on Bifurcation ¶¶ 116–124
The Articles 4(4) and 11 Objections are joined to the merits. Deciding them would largely repeat the breach analysis needed on the merits. Upholding them would do little to narrow the case, because the facts about Okhchuchay River pollution also support the claims under Articles 2, 3, 4(1) and 7. Decision on Bifurcation ¶¶ 125–129
Armenia withdrew its request for a preliminary ruling on the Attribution Objection, so the Decision does not address it. Decision on Bifurcation ¶ 40
Operative part: the Article 18 Objections will be ruled on in a preliminary phase, the merits are suspended under Article 14(5), the other objections are joined to the merits, and the decision on the costs of bifurcation is reserved. Decision on Bifurcation ¶ 132

Procedural history

18 January 2023Azerbaijan files its Notice of Arbitration under Article 18(2) of the Bern Convention and appoints Judge Bruno Simma.
18 April 2023Armenia appoints Judge Nicolas Michel.
5 July 2023The Tribunal is constituted when the co-arbitrators appoint Dr. Václav Mikulka as presiding arbitrator.
29 March 2024Procedural Order No. 1 adopts the Rules of Procedure.
15 May 2024Procedural Order No. 2 sets the procedural timetable.
12 February 2025Azerbaijan files its Statement of Claim.
12 June 2025Armenia files its Memorial on Preliminary Objections. Azerbaijan opposes bifurcation on 24 July 2025.
16 October 2025Hearing on Bifurcation at the Peace Palace, The Hague.
23 December 2025Decision on Bifurcation: the Article 18 Objections are bifurcated and the other objections are joined to the merits.
27 January 2026Procedural Order No. 3 sets the timetable for the preliminary objections phase, with a hearing scheduled for 16–18 March 2027.