(AP Photo/Susan Walsh)

WASHINGTON - The United States is considering how an international peacekeeping force might operate in Syria.

White House press secretary Jay Carney says the U.S. has begun looking at options for a peacekeeping force, perhaps administered by the United Nations or Arab nations. The Syrian military rejects calls for peacekeepers, calling such a move unjustified interference in internal affairs.

Carney said nothing about U.S. involvement in such a force, although the U.S. has contributed peacekeepers to some U.N. missions.

Carney says the focus now is on pressuring Syrian President Bashar Assad to stop a military campaign against protesters and give up power.

He called the government attack on civilians "disgusting."

With diplomatic efforts bogged down, the conflict is taking on the dimensions of a civil war.