Amid escalating tension with Russia over the seizure of three naval vessels, the Ukrainian parliament on Monday supported a bill imposing martial law in certain regions of the country for 30 days starting 9 a.m. local time on Wednesday.
On Sunday, the Ukrainian Navy said that Russian forces opened fire and seized three Ukrainian ships near the Kerch Strait, which separates the Black Sea and the Sea of Azov, injuring six Ukrainian military sailors.
Russia's Federal Security Service said that the Ukrainian ships breached the Russian border, and conducted dangerous manoeuvres in spite of Russia's warning.
The Ukrainian Navy said it had informed Russia in advance about the passage of its vessels from the Black Sea to the Sea of Azov through the Kerch Strait, calling Russia's actions an "act of aggression".
According to a statement on the parliament's website, the legislation, which enforces the presidential decree on the martial law, was supported by 276 votes in favour, surpassing the minimum of 226 required, Xinhua news agency reported.
Earlier Monday, Ukrainian President Petro Poroshenko signed a decree to put into force a decision of the National Security and Defense Council (NSDC) on imposing the martial law in the country for 60 days due to the tensions with Russia in the Sea of Azov.
However, later Poroshenko said he had decided to reduce the time under martial law to 30 days.
Besides, Poroshenko said that the law will be imposed not across the whole country, but only in the regions bordering Russia; Moldova's breakaway region of Transnistria, where Russian troops are stationed; and the regions located on the shores of the Black Sea and the Sea of Azov.
The Ukrainian president emphasised that "martial law does not mean the declaration of war", but a step towards strengthening Ukraine's defence.
Meanwhile, Oleksandr Turchynov, head of the NSDC, said that the martial law envisages imposing "temporary restriction of citizens' rights and freedoms".
According to the Ukrainian media, the martial law regime stipulates for a partial mobilisation of troops, curfew, a ban on demonstrations, restrictions on freedom of movement, control over the media activities, seizure of property for the needs of the defence ministry, among other measures.
Relations between Russia and Ukraine have been deteriorating since Crimea was incorporated into Russia in March 2014 following a local referendum that was rejected by Kiev and Western countries.
At the UN, meanwhile, political affairs chief Rosemary DiCarlo urged both Russia and Ukraine to step away from further confrontation at sea.
Briefing the Security Council, which met in the wake of Sunday's confrontation between vessels from the two neighbouring countries off the coast of Crimea, DiCarlo urged them "to refrain from any ratcheting up of actions or rhetoric".
An "immediate de-escalation" of tensions is needed in the Sea of Azov and the Black Sea, she said, underlining the importance of "earnest attempts" to find a peaceful resolution to years of simmering conflict between Russia and Ukraine, Xinhua reported.
"(We) remind both (Russia and Ukraine) of the need to contain this incident so as to prevent a serious escalation that may have unforeseen consequences," she said.