This article is more than 1 year old

This article is more than 1 year old

The Ukrainian president has proposed imposing martial law after Russian forces shot at and seized three Ukrainian navy vessels in the Black Sea, injuring six crew members according to Kiev, in a major escalation of tensions between the countries.

The seizure sparked protests by dozens of people outside the Russian embassy in Kiev. Some placed paper boats outside the residence while others threw smoke grenades and set fire to tyres piled up outside.

Ukrainian MPs were to vote on Monday on President Petro Poroshenko’s proposal following an emergency war cabinet on Sunday night. Poroshenko said the move was intended for defensive purposes and would not imply a declaration of war.

The UN security council was also holding an emergency meeting on Monday about the incident at the request of Ukraine.

Facebook Twitter Pinterest A National Guard officer extinguishes a torch thrown during a rally in front of the Russian embassy in Kiev. Photograph: Gleb Garanich/Reuters

Sunday’s hostilities began when Russia prevented three Ukrainian navy vessels from passing beneath its bridge in the Kerch strait by blocking the way with a cargo ship. Two artillery ships and a tug boat were subsequently fired on and seized. According to the FSB, Russia’s principal security agency, three Ukrainian sailors were wounded, but none of them were in a life-threatening condition.

The Kerch Strait connects the Sea of Azov with the Black Sea. Russia constructed a $3.69bn (£2.7bn) bridge over the strait after it occupied Crimea, to link the Russian mainland and the peninsula. The Russian president, Vladimir Putin, officially opened the bridge in May.

The FSB said its patrol boats had seized the three naval vessels after they entered its territorial waters illegally and carried out “provocative actions”.

“Their aim is clear – to create a conflict situation in this region,” the FSB said.

Ukraine said it had given Russia advance warning of the route being taken by its ships, which have to pass through the strait to reach the Sea of Azov.

Facebook Twitter Pinterest The Nikopol gunboat and the Yany Kapu tugboat of the Ukrainian navy docked in Russian-controlled Crimea. Photograph: Sergei Malgavko/Tass

The Russian news agency RIA said the Kerch strait had reopened to shipping on Monday morning.

In a televised war council meeting with Poroshenko, Ukrainian military commanders said 23 sailors had been taken captive by Russia and six had been wounded in fighting, two seriously.

Pavlo Klimkin, the Ukrainian minister of foreign affairs, said it was “likely possible that Russia plans further acts of aggression at seas or on the ground” and that Ukraine must be prepared.

The vote on martial law comes four months before presidential elections that Poroshenko is expected to lose. If Ukrainian MPs vote to suspend normal government, the elections could be postponed, prompting some observers to question whether Poroshenko was trying to exploit the incident.

The MP Mustafa Nayyem said on Facebook that “this whole story is complicated by the fact that, during martial law, the holding of presidential, parliamentary or local elections, as well as strikes, protests, rallies and mass demonstrations are forbidden”.

Martial law was not declared in Ukraine after the annexation of Crimea by Russia in 2014 or during the ongoing war in eastern Ukraine with Russian-backed forces.

Facebook Twitter Pinterest Russian jet fighters fly over a bridge connecting the Russian mainland with the Crimean peninsula. Photograph: Pavel Rebrov/Reuters

Poroshenko appealed to Ukraine’s allies to protect his country and stand united against Russian aggression.

Maja Kocijančič, the EU spokesperson for foreign affairs and security, has urged both sides to show restraint and “de-escalate the situation immediately” adding that the EU does not recognise the “illegal annexation” of Crimea by Russia.

Donald Trump has not responded to the incident, but as reports emerged the US president tweeted that the EU had failed to live up to its commitment to Nato, and that Europe should “pay their fair share for military protection”.

Nato called on Russia to ensure unhindered access to Ukrainian ports in the Sea of Azov in accordance with international law, calling for calm on both sides. Its spokeswoman, Oana Lungescu, said: “Nato is closely monitoring developments in the Azov Sea and the Kerch strait, and we are in contact with the Ukrainian authorities. We call for restraint and de-escalation.”

A correspondent for Rossiya-24, a Russian state-controlled TV channel, reporting from the Kerch strait bridge said Russia’s tactic with the cargo ship had completely blocked passage under the bridge and that Russian military aircraft were circling overhead.

The Ukrainian navy complained in September of “acts of provocation” by Russian border guards against its ships taking the same route.

Ukraine has recently increased the number of its naval vessels and border guard patrols in the Sea of Azov, in response to an increase in checks on commercial shipping by Russia.

Kiev and the west have accused Moscow of deliberately blocking ships from Mariupol, which has vital access to heavy industry in the region. Mariupol is near the area of eastern Ukraine controlled by Russian-backed separatists in a conflict that has caused at least 10,000 deaths since 2014.