Russia-Ukraine updates: US to ban Russian carriers from its airspace

Russia's parliament voted Tuesday to ratify a friendship treaty with two Russia-backed separatist areas in eastern Ukraine.

Lawmakers also added an amendment that brings the Treaty of Friendship into force immediately. The treaty includes a mutual defense pact, which establishes that Russian troops will jointly guard the borders of the self-proclaimed People’s Republics of Donetsk and Luhansk, in a breakaway region of eastern Ukraine known as Donbas.

Lawmakers were still discussing the decrees that Russian President Vladimir Putin signed on Monday night recognizing the two areas as independent. Both the upper and lower chambers of Russia's parliament are expected to vote soon on whether to ratify the orders.

It remains unclear exactly what borders Russia will recognize for the areas. Separatist leaders of the self-declared People’s Republics of Donetsk and Luhansk want to control all of the Donetsk and Luhansk regions in Donbas. But they currently only have about a third, with the rest controlled by Ukraine.

Some Russian officials have suggested Moscow may adopt the position that the separatist areas should include the entire Donetsk and Luhansk regions, thus raising fears that Russian troops will use force to expand the borders.

-ABC News' Patrick Reevell

Top Russian officials on Tuesday morning dismissed new sanctions being imposed by Western countries for Moscow's recognition of the separatist areas in eastern Ukraine.

In an interview with state-owned television channel Russia-24, Russian Foreign Minister Sergey Lavrov said the country was already "used to" sanctions and that more would be imposed regardless of what Moscow does.

"That our [Western] colleagues are trying to push the blame on Russia for the failure of the Minsk agreements, we also understand," Lavrov said. "Our European, American, British colleagues won't stop and won't calm down as long as they haven't exhausted their possibilities for the so-called punishment of Russia."

"They already threaten all possible sanctions. Hellish, or as they say there, 'the mother of all sanctions,'" he added. "Well, we're used to this. The president already noted our position, we know that sanctions will be introduced all the same, in any case. With a basis, without a basis."

Meanwhile, the speaker of Russia's parliament, Vyacheslav Volodin, echoed Lavrov's sentiments during an ongoing session of the lower house, known as the State Duma.

"Yes, sanctions hinder our development. But they would happen anyway. They would happen anyway even if that decision hadn't been taken," Volodin told lawmakers, adding that there are "more important problems."

"Yesterday, our president stopped a war," he said. "It's not a question of territory -- it's a question of the lives of millions of citizens."

-ABC News' Patrick Reevell

U.S. embassy staff who remained in Ukraine will return to the country on Tuesday after spending the night in Poland amid fears of a Russian invasion, a senior U.S. official told ABC News.

Personnel will return to the city of Lviv in western Ukraine, where they had relocated operations from the Ukrainian capital, Kyiv. But they are poised to move back to Poland at any point, the official said.

-ABC News' Martha Raddatz

Russia-backed separatists in eastern Ukraine have continued to accuse Ukrainian government forces of attacks.

The separatists in a breakaway region known as Donbas made another unverified claim Tuesday morning that three civilians were killed by a roadside bomb.

Separatist leaders posted photographs of a burned-out minivan on a road in their territory that they alleged was the vehicle blown up by a Ukrainian "diversionary group." The claim is unverified and resembles other allegations that have been rapidly debunked.

Meanwhile, a top separatist military commander accused Ukrainian government forces of continuing to shell the area.

The latest claims raise the possibility that Russia is still building a pretext to launch an attack on Ukrainian government troops, even after recognizing the self-proclaimed People's Republics of Donetsk and Luhansk as independent.

-ABC News' Patrick Reevell