President Obama's top national security advisers Tuesday were considering the possibility of new sanctions against Russia amid reports of armed skirmishes in eastern Ukraine between government forces and pro-Russian separatists.

"We are actively looking at our options," White House press secretary Jay Carney said.

Officials said any additional U.S. action was unlikely before a diplomatic gathering Thursday in Geneva, where Secretary of State John Kerry is scheduled to meet with his counterparts from Russia, Ukraine and the European Union.

The Geneva meeting, said State Department spokesman Jen Psaki, "is likely the next step here, because it's an opportunity for everybody to sit down at the table and have a discussion. At the same time, we can make preparations for any additional sanction steps we want to take."

Obama signed an executive order last month that would permit restrictions on financial dealings and licensing agreements with Russia's principal economic sectors - including energy and mining. Officials said the additional sanctions now under consideration probably would not go that far and that broader measures are being held in reserve to respond to any move by Russian troops to cross the eastern Ukraine border.

Although the United States and its allies have called repeatedly on Russia to negotiate directly with Ukraine's interim government, Russian Foreign Minister Sergei Lavrov has held only one brief meeting with his Ukrainian counterpart, Andrii Deshchytsia, since the crisis began in late February. Psaki made clear Tuesday that the administration sees the main goal of the Geneva meeting as putting Lavrov and Deshchytsia in the same room for a substantive discussion.

At the White House, Carney ruled out any U.S. military intervention, as well as any lethal military assistance to Ukraine.