A ceasefire agreement reached overnight by European leaders "represents a potentially significant step toward a peaceful resolution of the conflict" in Ukraine, the White House said Thursday.
But White House press secretary Josh Earnest warned that "the true test of today’s accord will be in its full and unambiguous implementation."
"This agreement must now be followed by immediate, concrete steps to fulfill the commitments by all parties," Earnest said. "The cease-fire must be implemented and honored. Heavy weapons must be withdrawn from the conflict zone, and Russia must end its support for the separatists and withdraw its soldiers and military equipment from eastern Ukraine."
The leaders of Russia, Ukraine, France and Germany announced that the cease-fire would take effect on Sunday, after an all-night negotiating session in Minsk, Belarus.
The deal will give the pro-Russian eastern regions full control over the border, in a concession to Moscow. The agreement will also create a de facto demilitarized zone, and grant greater political power to regions currently controlled by separatists. But it will not grant the regions full autonomy, as Russia has long demanded.
U.S. Ambassador to the United Nations Samantha PowerSamantha PowerHow Trump broke the system that offers protection to Afghan allies Aid airlift underway to earthquake-striken Haiti With Haiti in chaos, we must rewrite the script on disaster aid MORE stressed that the U.S. will be watching closely to see if Russia and the rebel fighters abide by the peace deal.
“Minsk agreements have come and gone in the past and have not been implemented, so our emphasis now is … making sure that this is not just … doing a peace deal with one hand and then passing out more surface-to-air missiles with the other, which is what it has looked like in the past,” Power said during an appearance on MSNBC’s “Morning Joe.”
Earnest also said the U.S. was particularly concerned about reports that fighting had intensified upon announcement of the deal.
President Obama phoned Russian President Vladimir Putin ahead of the negotiations to warn the Russian leader that the U.S. would continue to escalate costs if no deal was struck and implemented.
Earlier this week, Obama acknowledged he was contemplating sending Ukraine lethal, defensive military weapons, despite warnings from Moscow and European partners that doing so could inflame the situation.
"What I’ve asked my team to do is to look at all options — what other means can we put in place to change Mr. Putin’s calculus — and the possibility of lethal defensive weapons is one of those options that’s being examined," Obama said. "But I have not made a decision about that yet."
--This report was updated at 11:45 a.m.