Washington: The influential pro-Israel American Israel Public Affairs Committee (Aipac) will deploy hundreds of activists next week to win support in Congress for military action in Syria, amid an intense White House effort to convince wavering US 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 Aipec source said on Saturday.

Congressional aides said they expected the meetings and calls on Tuesday, as President Barack Obama and officials from his administration make their case for missile strikes over the apparent use of chemical weapons by Syrian President Bashar Al 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 US Senate is due to vote on a resolution to authorise the use of military force as early as Wednesday. Leaders of the House of Representatives have not yet said when they would vote, beyond saying consideration of an authorisation is “possible” sometime this week.

Obama has asked Congress to approve strikes against Al Assad’s government in response to a chemical weapons attack on August 21 that killed more than 1,400 Syrians.

But many Republicans and several of Obama’s fellow Democrats have not been enthused about the prospect, partly because war-weary Americans strongly oppose getting involved in another Middle Eastern conflict.

Pro-Israel groups 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.

Supporters of the groups and government sources acknowledged they had made it known that they supported US action, concerned about instability in neighbouring Syria and what message inaction might send to Al Assad’s ally, Iran.

But they had generally wanted the debate to focus on US national security rather than how a decision to attack Syria might help Israel, a reflection of their sensitivity to being seen as rooting for the United States to go to war.