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

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

Ukrainian Defense Minister Oleksii Reznikov took to Twitter early Tuesday to dismiss Moscow's recognition of the Russian-controlled breakaway areas in eastern Ukraine, saying the move amounts only to a recognition of the Kremlin’s "own aggression."

"We remain confident and calm," Reznikov tweeted. "We are ready and able to defend ourselves and our sovereignty."

But he also issued a warning: "World cannot be silent."

"Sanctions?" he tweeted. "Another brick in the wall? New Berlin Wall?"

U.S. Secretary of State Antony Blinken early Tuesday called Russia's move to recognize separatist regions in Ukraine as independent a "predictable" act. 

"Russia’s move to recognize the 'independence' of so-called republics controlled by its own proxies is a predictable, shameful act," he said on Twitter. 

Blinken is scheduled to meet Ukrainian Foreign Minister Dmytro Kuleba in Washington on Tuesday.

U.S. Secretary of State Antony Blinken spoke by phone on Monday with Ukrainian Foreign Minister Dmytro Kuleba, noting the Biden administration's "swift response" to Russia's decision to recognize Ukraine's separatists' regions as independent. 

"They discussed the strong measures we announced today in response and reiterated that additional steps would be forthcoming," State Department spokesperson Ned Price said in a statement late Monday.

Blinken and Kuleba are scheduled to meet on Tuesday in Washington.

Kuleba earlier said he spoke with Blinken about sanctions. 

"I underscored the need to impose tough sanctions on Russia in response to its illegal actions," Kuleba said on Twitter. 

-ABC News' Chad Murray and Conor Finnegan