EU and NATO are working on their measures in response to the seizure by Russia of three Ukrainian naval boats with their crew off the coast of Russian-annexed Crimea.
"We expect Russia to ensure the resumption of a free passage through the Kerch Strait and that the captures vessels a released," EU Commission spokesperson Maja Kocijancic said.
When was asked about possibility of new sanctions against Russia she answered, that any restrictive measures 'must be adopted unanimously', and reminded reporters of the many sanctions already in place linked to Ukraine and Crimea.
NATO ships are allowed into the Black sea for a limited time and without heavy weapons.
"I think NATO should seriously consider discussing increasing it's military presence in the Black Sea. One concrete measure is to send more often NATO warships to important port cities in Georgia or in Ukraine to show solidarity," remarked Bruno Lete, from the German Marshall Fund.
NATO is already training Ukrainian army, providing it with anti-tank missiles.
"The US should provide Ukraine with military assistance that is defensive in nature, for example radars, intelligence, surveillance and reconnaissance assets for maritime domain awareness, I would say land-base anti-ship missiles for defense of Ukraine Azov sea littoral," explained Michael Carpenter, expert from the Atlantic Council.