WASHINGTON (Reuters) - President Barack Obama remains committed to diplomatic efforts to end the violence in Syria, the White House said on Tuesday, despite calls from a leading Republican senator for military action against the government of President Bashar al-Assad.

"The President has repeatedly called for an immediate halt to the violence in Syria. Currently the administration is focused on diplomatic and political approaches rather than a military intervention," said Tommy Vietor, a White House spokesman.

"Our best chance to do that and to usher in a political transition is to continue to isolate the regime, cut off key revenue streams, and push the opposition to unite itself under a clear transition plan that makes space for Syrians of all creeds and ethnicities," he said.

On Monday, Senator John McCain said the United States should lead an international effort to protect Syrian cities and towns through air strikes on Syrian government forces.

(Reporting By Missy Ryan; Editing by Paul Simao)