(Updates with comments from AIPAC and Boxer)
By Patricia Zengerle
WASHINGTON, Nov 25 (Reuters) - U.S. Senate Majority Leader Harry Reid said on Monday the Senate will consider legislation next month to impose tighter sanctions on Iran, but only after studying the issue and possibly holding hearings.
Reid said he would look to fellow Democrats Tim Johnson, chairman of the Banking Committee, and Robert Menendez, who heads the Foreign Relations Committee, for a decision after the Senate returns from its Thanksgiving holiday recess on Dec. 9.
"They will study this, they will hold hearings if necessary, and if we need work on this, if we need stronger sanctions, I am sure we will do that," Reid said on National Public Radio.
The decision on sanctions could be central to prospects for the interim agreement to curb Iran's nuclear program announced in Geneva on Sunday. The White House - and the Iranian government - have said Congress could kill the deal if it enacts new sanctions now.
Comments from Reid and other lawmakers bolstered expectations that the Senate would likely proceed as the White House wants, and hold off on imposing new sanctions for the next six months as negotiations continue.
Senator Barbara Boxer, a California Democrat, said sanctions relief under the deal "could and should" be withdrawn if Iran does not meet terms of the interim pact. But she said lawmakers should not underestimate the deal's importance.
"I am deeply disappointed by the negative reactions we have been hearing from some of my colleagues to the preliminary agreement," Boxer said in a statement on Monday.
The accord was met with deep skepticism from some members of Congress, who tend to be more hawkish about Iran than President Barack Obama's administration.
A number of lawmakers, especially Republicans, insisted they would try to enact stiffer new sanctions despite the deal. Hawkish pro-Israel lobbyists had been pushing American lawmakers hard to keep to a tough line on Israel's arch-foe, Tehran.
The American Israel Public Affairs Committee issued a memo to supporters on Monday raising doubts about many terms of the interim agreement, including that it allows Iran to continue uranium enrichment.
But the pro-Israel advocacy group did not call for new sanctions to be imposed right away. AIPAC said it supported legislation that would allow sanctions to take effect if Iran violates the interim pact or does not agree to an "acceptable" comprehensive deal.
Reid said he had spoken to Israeli Prime Minister Benjamin Netanyahu and understood his concerns. Netanyahu has described Sunday's interim deal as a historic mistake that gives Iran too much leeway to continue work that could produce a bomb.
"That's why I have indicated that I will take a look at this when I get back, all aspects of it. But we all have to acknowledge that it's an important first step," Reid said.
The comments were the first on the issue from the Senate leader since negotiators in Geneva reached an interim accord in which Iran will reduce its nuclear activity in exchange for some relief from international sanctions. The West says Iran's nuclear program is aimed at developing weapons, but Tehran says it is for civilian use.
The Republican-controlled House of Representatives approved a package of tighter sanctions on Iran in July by a vote of 400 to 20. But similar legislation has been held up in the Democratic-controlled Senate for months after the Obama administration asked for a delay to let talks go ahead.
Reid also said he would seek input from Republicans. (Editing by Doina Chiacu)