The International Tribunal for the Law of the Sea (ITLOS) has delivered its Order of 25 May 2019 in respect of Case No. 26, Case concerning the detention of three Ukrainian naval vessels (Ukraine v. Russian Federation), Provisional Measures. The Tribunal concluded that prima facie the UNCLOS Annex VII arbitral tribunal would have jurisdiction over the submitted dispute. The Tribunal prescribed various provisional measures under Article 290(5) of UNCLOS.
For an overview see the press release. Two Declarations, three Separate Opinions and one Dissenting Opinion were appended to the Order of 25 May 2019, available here. Ukraine and Russia have both responded through their respective Ministry of Foreign Affairs.