(Corrects name of White House spokesman to Jay Carney from John Carney in second paragraph)
WASHINGTON, April 15 (Reuters) - Ukraine's actions against pro-Russian militiamen in the country's eastern region are justified because of the threat to law and order, the White House said on Tuesday.
With rising concern at Russia's role in stirring unrest, the United States is "seriously considering" new sanctions against Russia, but is not considering providing lethal aid to Ukraine, White House spokesman Jay Carney said at a briefing.
Carney praised the Kiev government for saying it intends to move forward gradually and responsibly with a military operation it begun on Tuesday against militiamen in Russian-speaking eastern Ukraine. He urged caution, however, and said tensions could be defused if Russia would pull its troops back from the border, cease support for separatist activities, and engage in negotiations.
"The Ukrainian government has the responsibility to provide law and order and these provocations in eastern Ukraine are creating a situation in which the government has to respond," Carney told reporters.
The United States continues to plan to participate in talks scheduled for Thursday between the Russian and Ukrainian governments, the United States and the European Union, Carney said.
President Barack Obama told Russian President Vladimir Putin in a phone call on Monday that Moscow would face further costs for its actions in Ukraine. The United States has already imposed three rounds of sanctions against Russia in response to Moscow's annexation of Crimea in southern Ukraine last month.
The next round of sanctions is likely to target Russians close to Putin as well as Russian entities, sources familiar with the discussions have said.
"We are looking forward to this meeting on Thursday to see whether or not there is - the potential, anyway - for moving forward on diplomatic resolution," Carney said. (Reporting By Mark Felsenthal; Editing by Sandra Maler and Grant McCool)