Ukrainian President Petro Poroshenko on Thursday visited a military air base in the city of Zhytomyr where Ukraine's Air Assault Forces troops were preparing to leave for the locations on the border with Russia.

The Ukrainian parliament also voted on not to prolong the friendship treaty with Russia on Thursday, which is up for renewal next April, and adopted a bill that unilaterally doubles the extent of Ukraine's territorial waters to 24 nautical miles.

Ukrainian authorities said this will allow the coast guard and the navy to be more efficient in patrolling the area to prevent military threats and smuggling.

The bill also allows Ukrainian border guards to open fire without warning on potential attackers.

The long-simmering conflict between Russia and Ukraine that started with Russia's annexation of Crimea spilled into the open on Nov. 25 when the Russian coast guard fired upon and seized three Ukrainian naval vessels and their crews.

Ukrainian President Petro Poroshenko responded to the standoff by introducing martial law for 30 days, something Ukraine had not done even after Crimea's annexation and amid large-scale fighting between Ukrainian forces and Russia-backed separatists in 2014-2015.

As part of martial law, Ukraine has beefed up its forces on the border with Russia, called up reservists for training and barred entry to all Russian males aged between 16 and 60.