WASHINGTON — Faced with deepening crises in the Middle East and Ukraine, President Barack Obama is putting the brakes on the notion that American military power can solve either conflict.

While that stance is in keeping with Obama’s long-standing aversion to military entanglements, it comes at a time when the effectiveness of his preferred options is being challenged and there are indications that some in the administration are ready to take more robust actions.

In the conflict between Russia and Ukraine, Obama has relied largely on coordinated U.S. and European Union sanctions to try to shift Russian President Vladimir Putin’s calculus. While the White House can claim credit for inflicting some pain on Russia’s economy, Putin appears to be only getting more aggressive, with Ukrainian officials accusing Russia of sending two military columns across the border Thursday.

During a news conference at the White House, Obama warned that Russia likely will face more Western penalties because of its continued provocations. But he offered no indication that he was considering anything outside the realm of sanctions and explicitly ruled out the prospect of U.S. military intervention.

“We are not taking military action to solve the Ukrainian problem,” Obama said.