WH: Biden raises concerns with Putin about Ukraine

The White House says President Joe Biden has called on Russian President Vladimir Putin on Tuesday to "de-escalate tensions" following a Russian military buildup on Ukraine's border.

It says Biden also told Putin the U.S. would "act firmly in defense of its national interests" regarding Russian cyber intrusions and election interference, according to the White House.

Biden proposed a summit meeting in a third country "in the coming months" to discuss the full range of U.S.-Russia issues, the White House said.

The call comes as concern rises in the West about a surge of cease-fire violations in eastern Ukraine, where Russia-baсked separatists and Ukrainian forces have been locked in a conflict since Moscow's 2014 annexation of Ukraine's Crimean Peninsula.

Biden "emphasized the United States' unwavering commitment to Ukraine's sovereignty and territorial integrity," press secretary Jen Psaki said at the White House briefing, adding that he made clear that Russia must "de-escalate tensions."

More than 14,000 people have died in fighting in eastern Ukraine, and efforts to negotiate a political settlement have stalled. Over the past week, there have been daily reports of Ukrainian military casualties and rebels also have reported losses.

Ukraine has said Russia has massed 41,000 troops at its border with eastern Ukraine and 42,000 more in Crimea. Russia's defense minister said Tuesday the buildup was part of readiness drills in response to what he described as threats from NATO, and he said the maneuvers in western Russia would last for two more weeks.

Earlier Tuesday, Secretary of State Antony Blinken, who was in Brussels for meetings with NATO allies, accused Russia of taking "very provocative" actions with the amassing of troops.

NATO chief Jens Stoltenberg also called the Russian movements "unjustified, unexplained and deeply concerning."

Psaki said "there is coordination on the international front" with European partners to "put the pressure on and call for what's right."

Psaki also said the conversation and upcoming summit plans do "not change the calculations, the the process, the review that has been ongoing" with regard to sanctions against Moscow.

"The president was clear that there will be consequences, as he has said publicly, some will be seen and some will be unseen, as we often say, and hopefully we'll have more to share with all of you soon," she added.