The influential pro-Israel American Israel Public Affairs Committee will deploy hundreds of activists this week to win support in Congress for military action in Syria, amid an intense White House effort to convince wavering U.S. lawmakers to vote for limited strikes.
"We plan a major lobbying effort, with about 250 activists in Washington to meet with their senators and representatives," an AIPAC source said on Saturday.
Congressional aides said they expected the meetings and calls to take place on Tuesday, as U.S. President Barack Obama and officials from his administration made their case for missile strikes over the alleged use of chemical weapons by Syrian President Bashar Assad's government.
The vote on action in Syria is a significant political test for Obama, and a major push by AIPAC, considered one of the most powerful lobbying groups in Washington, could provide a boost.
The U.S. Senate is due to vote on a resolution to authorize the use of military force as early as Wednesday. Leaders of the House of Representatives have not yet said when they will vote, beyond saying consideration of an authorization is "possible" sometime this week.
But many Republicans and several of Obama's fellow Democrats have not been enthusiastic about the prospect, partly because war-weary Americans strongly oppose becoming involved in another Middle Eastern conflict.
The pro-Israel group had largely kept a low profile on Syria as the Obama administration sought to build its case for limited strikes after last month's attack on rebel-held areas outside Damascus.
AIPAC supporters and government sources acknowledged that the group had made it known that it supported U.S. action and was concerned about instability in Syria, which borders Israel, and what message inaction might send to Assad's ally, Iran.
But AIPAC generally wanted the debate to focus on U.S. national security, rather than on how a decision to attack Syria might help Israel, a reflection of its sensitivity to being seen as rooting for the U.S. to go to war.