Russia should immediately free of the Ukrainian sailors and the ships taken over during the "Kerch incident," a NATO official told Interfax in Brussels.

"NATO has made repeatedly clear that there was no justification for Russia's use of military force against Ukrainian ships and military personnel. We continue to call on Russia to release the Ukrainian sailors and ships without delay," the source said, responding to a relevant question, on Saturday evening.

The source cited the statement made by the North Atlantic Council on November 28, 2018 and the press conference given by NATO Secretary General Jens Stoltenberg on April 4, 2019, where he called Russia to free the Ukrainian sailors and the ships taken over near the Sea of Azov in 2018.

According to earlier reports, the United Nations' International Tribunal for the Law of the Sea (ITLOS) on Saturday issued a ruling on the claim filed by Ukraine, which sought interim measures against Russia on April 16, 2019 and demanded the release of the Ukrainian sailors and the vessels detained din the Kerch Strait area in November 18,

The tribunal ruled to release the sailors and the Ukrainian vessels.

The Russian Foreign Ministry, however, believes the ITLOS does not have the jurisdiction to adjudicate the "Kerch incident." The ministry issued a relevant statement on April 16.

On November 25, 2018 armed Russian border guards detained the Ukrainian tug boat Yany Kapu and small armored artillery boats, Berdyansk and Nikopol, which were heading from Odesa to Mariupol. The vessels were convoyed to Kerch.

The 24 Ukrainians who were on board, including two national security officers, have been charged with "illegal border crossing by a group of accomplices or an organized crime group, or with the use or threat of violence " (Part 3 three of Article 322 of the Russian Criminal Code).

The crime is punishable by up to six years in prison, The Ukrainians were transferred to Moscow in late November.