The White House on Friday voiced “deep concern” over reports that armed forces were patrolling a pair of airports in Ukraine's Crimean region.
The reports have intensified concerns that the Russian military might be acting within the former Soviet republic.
Carney also dismissed comments made by Ukranian President Viktor Yanukovych at a press conference in the Russian city of Rostov-on-Don, 40 miles from the border.
During the press conference, Yanukovych accused the U.S. and other Western powers of a “gangster coup.”
“The disturbances and victims are the consequences of the political crisis, the result of the irresponsible policies of the West, which encouraged the [opposition movement] Maidan,” Yanukovych said.
Carney said Yanukovych had abandoned his responsibilities in Kiev and suggested he had forfeited his legitimacy by fleeing.
According to multiple media reports, dozens of armed and masked men seized government administration buildings and airports in the Crimean region, where pro-Russian sentiment is high. The move came a day after Russia performed military exercises near the border with Ukraine, and pro-Western leaders in Kiev suggested the forces could be Russian soldiers.
“There have been some reports that suggest intervention, and we're concerned about those,” Carney said.
The White House spokesman said Russian military movement would be “inconsistent” with Moscow's international obligations, and called on Russia to “respect” Ukrainian sovereignty. He added that the U.S. was “seeking clarification” on the situation, and that the administration was “very focused” on helping nurture a transitional government in Ukraine.