U.S. officials say a series of urgent White House meetings this week could bring a decision on whether to arm Syrian opposition rebels.
Aides from the State and Defense Departments and other agencies have prepared the groundwork for a top-level meeting Wednesday between President Barack Obama and his national security staff. The meeting was made urgent by concerns that pro-government forces backed by Iran and Lebanon's Hezbollah militia may be gaining the upper hand in the Syrian conflict.
A State Department spokeswoman says a "wider range of options" has been prepared for the president's consideration.
Syrian opposition leaders have warned the U.S. that their rebellion could face devastating losses without greater support.
As many as 5,000 Hezbollah fighters are now in Syria, helping the government pursue its military campaign after capturing the town of Qusair near the Lebanese border last week. Syrian forces apparently are now poised for an attack on the strategic city of Homs.
Although a decision has not been made, U.S. officials say Mr. Obama is learning toward sending weapons to moderate rebel units. The president already has ruled out any intervention that would require U.S. military forces inside Syria.
Other options, such as deploying American air power to enforce a no-fly zone over Syria, while far less likely, are now being more seriously debated.
Any intervention essentially would pit the U.S. and regional allies Saudi Arabia, Turkey and Qatar in a proxy war against Iran, the main arms provider for the Syrian government, and Hezbollah, which is increasingly supplying the manpower.