KIEV: Ukraine’s president signed an act imposing martial law in border regions on Wednesday as mounting tensions over Russia’s seizure of Ukrainian ships saw US President Donald Trump threaten to cancel talks with Vladimir Putin.

President Petro Poroshenko’s spokesman confirmed he had signed the act, which introduces martial law for 30 days in 10 regions bordering Russia, the Black Sea and the Azov Sea.

The move came after Poroshenko warned of a build-up of Russian forces near Ukraine’s borders, escalating the most dangerous crisis in years between the ex-Soviet neighbours.

Western governments have accused Russia of acting illegally in seizing the three ships and Trump has said he is considering cancelling planned talks with Putin at this week’s G20 summit in Buenos Aires.

Trump said he would make a final decision after hearing a report from national security advisors on this weekend’s incident.

“That will be very determinative,” Trump told The Washington Post. “Maybe I won’t have the meeting.”

Russian border patrol boats fired on, boarded and seized the three Ukrainian vessels, along with 24 sailors, on Sunday off the coast of Crimea.

The Ukrainian vessels — a tug and two gunboats — were trying to pass through the Kerch Strait from the Black Sea to the Azov Sea, but were refused access and chased into international waters by 10 Russian vessels.

Poroshenko said on Tuesday that the number of Russian units near the border with Ukraine had “grown dramatically”, with a threefold increase in the number of Russian tanks.

“I don’t want anyone to think this is fun and games. Ukraine is under threat of full-scale war with Russia,” Poroshenko said.

The Ukrainian parliament on Monday voted in favour of Poroshenko’s request for martial law, which gives authorities the power to mobilise citizens with military experience, regulate the media and restrict public rallies in affected areas.

It was unclear how it would be applied in the border areas and Poroshenko has suggested it is meant essentially as a preventative measure.

The prospect of martial law had already led to the relocation of a football match scheduled for Thursday between Arsenal and Ukrainian side FC Vorskla to Kiev from the city of Poltava, even though Poltava is not in one of the affected regions.

Russian military officials said on Wednesday that Moscow would soon deploy more of its advanced S-400 air defence systems in Crimea, which Russia annexed from Ukraine in 2014.

One more of the systems would be joining three others already deployed in Crimea, they said.

Kiev has angrily demanded the return of its ships and the release of its sailors, but on Tuesday a court in Crimea ordered 12 of them to be held in pre-trial detention for two months.

Three hospitalised sailors were also formally detained for two months. The rest are to appear in court on Wednesday.

Published in Dawn, November 29th, 2018