Ukraine’s parliament is to decide whether to bring in martial law as anger over the capture of three of its naval vessels by Russia spilled into the streets overnight.

“We gathered here today to protest against Russians over their actions today, over shooting of our military,” Oleksiy Ryabov told Reuters news agency.

“We are very angry. We should have severed all diplomatic relations with this country a long time ago.”

During a meeting of Ukraine’s National Security and Defence Council, President Petro Poroshenko described the Russian actions as “unprovoked and crazy”.

He said he would suggest martial law was brought in to parliament on Monday.

Tensions have recently risen in the Black Sea and the Sea of Azov off the Crimean peninsula – annexed by Russia in 2014.

How did the crisis unfold?

The crisis began when Russia accused the Ukrainian ships of illegally entering its waters.

In the morning, Ukraine’s Berdyansk and Nikopol gunboats, and the Yana Kapa tug, tried to sail from the Black Sea port of Odessa to Mariupol in the Sea of Azov, which is shared between the two countries.

Russia’s FSB later confirmed that one of its patrol boats had used force to seize the three Ukrainian vessels but said only three sailors had been wounded.

Ukraine said it had informed the Russians of its plan to move its ships through the sea to Mariupol.

Blame game

Tension between Russia and Ukraine has been building for months off Crimea.

Under a 2003 treaty between Moscow and Kiev, the Kerch Strait and the Sea of Azov are shared territorial waters.

So, expect Moscow to pin the blame for what happened on Sunday and for whatever happens next on President Poroshenko’s government.

What’s the background to this?

The shallow Sea of Azov lies east of Crimea, and south of the Ukrainian regions partially seized by pro-Russian separatists.

The two Ukrainian ports on its northern shore – Berdyansk and Mariupol – are key to exporting grain and produce such as steel, also for importing coal.

More than 10,000 people have been killed in the eastern Donetsk and Luhansk regions since separatists moved against the Ukrainian state in April 2014.

Ukraine and the West accuse Russia of sending its troops to the region and arming the separatists.

Moscow denies this but says that Russian volunteers are helping the rebels.