The EU has repeatedly stated its expectation that Russia immediately and unconditionally release the 24 captured Ukrainian sailors.

The European Union has responded to a recent decision by Moscow's court to extend captive Ukrainian sailors' detention for another three months.

"While the sailors remain detained, Russia must respect their right to legal representation, unhindered access by consular authorities, and ensure that all crewmen receive appropriate medical treatment as several of them were wounded during the capture," Spokesperson for Foreign Affairs and Security Policy/European Neighbourhood Policy and Enlargement Negotiations Maja Kocijancic said in a statement on April 17.

Read alsoUkrainian sailors to remain in custody in Moscow for another three months

The Lefortovo Moscow City Court on April 17 again extended the detention of 24 Ukrainian servicemen until the end of July 2019. Their detention was initially ordered by the court of Simferopol in the illegally-annexed Crimean peninsula.

"The European Union Delegation in Moscow along with a number of EU diplomatic missions were observing the proceedings at the Lefortovo Moscow City Court until the moment when the hearings were declared closed to the public," the statement said.

The EU has repeatedly stated its expectation that Russia immediately and unconditionally release the 24 captured Ukrainian sailors.

The servicemen have been held since November 25, 2018, when they were captured and their vessels seized near the Kerch Strait by Russia using military force with no justification.

The EU has responded to the escalation at the Kerch Strait by adding Russian officials to the list of those subject to restrictive measures in respect of actions undermining or threatening the territorial integrity, sovereignty and independence of Ukraine.

"We expect Russia to ensure unhindered and free passage through the Kerch Strait to and from the Azov Sea, in accordance with international law," the statement said.