The American Israel Public Affairs Committee (Aipac), the main pro-Israel lobbying group in Washington, has launched a major campaign to convince members of Congress to vote in favour of US military intervention in Syria.

Aipac’s drive has included dispatching more than 250 leaders and activists to lobby Congress, starting from this week, Politico reported.

In a statement released earlier this month, the group said: “The civilised world cannot tolerate the use of these barbaric weapons, particularly against an innocent civilian population including hundreds of children.”

A broad coalition of Jewish and pro-Israel groups — including the Anti-Defamation League, the American Jewish Committee, the Simon Wiesenthal Centre and the Republican Jewish Coalition — have joined Aipac in supporting President Barack Obama’s call for authorisation of a strike.

Mr Obama has repeatedly invoked Israel in his efforts to convince the American public and lawmakers to support the Syria measure.

Mr Obama has also found an unlikely ally in Sheldon Adelson, the Republican casino magnate who spent $70m of his personal fortune trying to defeat Mr Obama in last year’s election.

Mr Adelson told the National Journal that he supports the White House’s call for a strike and that he would be willing to help out the administration because it is “the right thing to do”.