JERUSALEM — The American Israel Public Affairs Committee, the powerful pro-Israel lobby in Washington, plans to dispatch 300 of its members to Capitol Hill on Tuesday as part of a broad campaign to press Congress to back President Obama’s proposed strike on Syria, the group said Monday.

The push by the group, known as Aipac, which included asking its supporters to call members of Congress, came as Israeli newspapers reported Monday that President Obama urged Prime Minister Benjamin Netanyahu to get personally involved in lobbying Congress. The reports said that Mr. Netanyahu had called several members himself.

But while those reports could not be confirmed, the intense push by Aipac and other Jewish and pro-Israel groups put Israel in a bind, after a week of trying to stay on the sidelines of the debate. Mr. Netanyahu’s government strongly supports an American strike to punish President Bashar al-Assad of Syria for his apparent use of chemical weapons, and as a warning to his Iranian patrons. But Israelis are deeply worried about being blamed by a wary American public for another military gambit in the Middle East, or of losing their broad bipartisan support if they land on the wrong side of the vote.

“It is a major dilemma, what Israel should do on the Hill,” a senior Israeli official said Monday, speaking on the condition of anonymity because of a dictate from Mr. Netanyahu not to discuss the Syria situation publicly. “We don’t want to be identified with pressing for a strike. This is not for us — we don’t want anybody to think this is for us,” the official said. “But if the president asks us for assistance, who are we to refuse?”