The Ukrainian military on Tuesday said two soldiers have been killed and 18 wounded in shelling by pro-Russian separatists in eastern Ukraine in the past 24 hours, the most casualties this year, as cease-fire violations increase.

The military said on its Facebook page it had recorded 84 cases of shelling by separatists who it said had opened fire on about 40 settlements along the front line using heavy artillery, in breach of cease-fire agreements.

"Three violations by the Russian army have been recorded during the past day, two of which with the use of weapons prohibited by the Minsk agreements. Russian occupation forces fired at Shchastia city with automatic grenade launchers. Twice Mariupol – from 122 mm caliber artillery, 120 mm caliber mortars," the statement said.

Ukraine has accused Russia of provoking the violence, saying Moscow used it as a pretext to formally recognize eastern Ukraine as independent and move its troops into the region, precipitating a crisis that the West fears could unleash a major war.

Meanwhile, the separatists accused the Ukrainian side of the shelling. The Luhansk People's Republic (LNR) said it has recorded 65 shellings by the armed forces, which damaged 14 houses in the territory not controlled by the Ukrainian authorities. The Donetsk People's Republic (DNR) claimed there were a series of shellings on Tuesday morning in Donetsk and Mariupol. It also reported civilian casualties.

Over the past few days, the security situation in eastern Ukraine has deteriorated significantly. Leaders of the DNR and LNR announced the evacuation of their residents to Russia on the afternoon of Feb. 18. They attributed this to rising tensions in the region. Militant leaders also announced a general mobilization.

In a lengthy televised address on Monday packed with grievances against the West, a visibly angry Russian President Vladimir Putin said eastern Ukraine was ancient Russian land.

Putin delved into history as far back as the Ottoman Empire and expressed frustration that Russia's demands for a rewriting of Europe's security arrangements had been repeatedly rebuffed.

"I deem it necessary to make a decision that should have been made a long time ago – to immediately recognize the independence and sovereignty of the Donetsk People's Republic and the Lugansk (Luhansk) People's Republic," Putin said.

Russian-backed separatists in Ukraine's Donetsk and Luhansk regions broke away from Ukrainian government control in 2014 and proclaimed themselves independent "people's republics." Russia needed to ratify its friendship treaties with the two breakaway regions before it could discuss matters like the exact borders of the territories, RIA news agency reported, citing the foreign ministry. Russia's parliament is expected to review friendship treaties on Tuesday.

Ukrainian President Volodymyr Zelenskyy, who received a call from United States President Joe Biden to express solidarity on Monday, accused Russia of wrecking peace talks and ruled out territorial concessions.

The clashes came a day after Putin's announcement, which drew international condemnation and immediate U.S. sanctions, with Biden signing an executive order to halt U.S. business activity in the breakaway regions. France and Germany also agreed to respond with sanctions, and Britain and the U.S. said they would announce further measures on Tuesday.

"The United States will impose sanctions on Russia for this clear violation of international law and Ukraine sovereignty and territorial integrity," Linda Thomas-Greenfield, U.S. ambassador to the United Nations, told reporters after an emergency meeting of the Security Council late on Monday. "We can, will and must stand united in our calls for Russia to withdraw its forces, return to the diplomatic table and work toward peace."

Britain said it had drawn up sanctions to target those complicit in the violation of Ukraine's territorial integrity, and those measures would come into force on Tuesday.

China called for all parties to exercise restraint while Japan said it was ready to join international sanctions on Moscow in the event of a full-scale invasion.

Russian U.N. Ambassador Vassily Nebenzia warned Western powers to "think twice" and not worsen the situation.

Rising fears of a major war in Europe pushed oil prices to a seven-year high on Tuesday, while safe-haven currencies like the yen rallied and global stocks tumbled. The rouble extended its losses as Putin spoke, at one point sliding beyond 80 per U.S. dollar.