Ukrainian President Petro Poroshenko signed a decree on Monday to introduce martial law for 60 days, a statement on his website said, though it needs parliamentary approval to come into force.
The decision came a day after Russia fired at and captured three Ukrainian vessels, triggering a sharp escalation in tensions between the two countries.
Parliament was expected to debate the decree later on Monday though a televised session of a parliamentary committee unanimously supported it.
Ukrainian legislation on martial law allows for a slew of curbs, including restrictions on movement and peaceful assembly, curfews, and restricting the media, though Poroshenko’s decree made no specific references to such restrictions.
Eleven measures outlined in the decree provide for mobilizing reserve forces, organizing the air defence of important state facilities and taking urgent steps to bring in enhanced cyber security measures and ensure public order.
There was no mention of a presidential election due to be held in March. Poroshenko’s move has prompted speculation by critics and opposition politicians that he might use it to delay the vote.
A twelfth provision of the decree was not published.
On Sunday, Russia seized three Ukrainian naval ships off the coast of Russia-annexed Crimea after opening fire on them and wounding several sailors.
Russia’s FSB security service said early on Monday its border patrol boats had seized the Ukrainian naval vessels in the Black Sea and used weapons to force them to stop, Russian news agencies reported.
The FSB said it had been forced to act because the ships – two small Ukrainian armoured artillery vessels and a tug boat – had illegally entered its territorial waters, attempted illegal actions, and ignored warnings to stop while manoeuvring dangerously.