Divisions within Republican ranks emerged Friday over a U.S.-Russia nuclear arms control treaty as President Barack Obama pushes for the Senate to act quickly on the pact.

Twenty-two Republicans — just over half the current GOP lawmakers in the Senate — wrote to their leader, Mitch McConnell of Kentucky, urging him not to allow the debate to be rushed in Congress' lame-duck session.

"We have numerous amendments requiring significant debate to the treaty as well as the resolution of ratification that we would like to offer and have votes on," the senators wrote. "It would be unwise and improper to do this in a hurried fashion over the course of only a few days."

The letter comes amid signs that Obama had gained ground in getting the Senate to ratify the treaty before the end of the year. Several leading Republicans had signaled a willingness to vote for the treaty if their concerns about modernizing the remaining nuclear arsenal are addressed.

The treaty would cut the limits on strategic warheads to 1,550 for the United States and Russia from the current ceiling of 2,200. The pact also would establish new procedures to allow both countries to inspect each other's nuclear arsenals to verify compliance.

Republicans, led by Sen. Jon Kyl, R-Ariz., have rejected Obama's insistence that the treaty must be dealt with amid the pressing business of the session. Some have raised concerns that the treaty would limit work on a missile defense system, and they have pressed for sufficient funds for modernization of the existing nuclear stockpile.

Kyl indicated on Thursday that he would support bringing the treaty to the floor if there is enough time for debate after lawmakers resolve critical tax and budget matters.

"If we can get this tax issue done and get the spending for the government accomplished, then there might be time to do it, if Leader (Harry) Reid doesn't then want to bring up that whole long list of other things that we talked about," Kyl told Fox News' Greta Van Susteren in an interview.

He also said that he thought Republicans would be happy to give the White House an agreement to consider the treaty around March, as long as the new senators coming in January were adequately briefed.

Democrats have made the treaty a priority because their ranks will shrink in January when newly elected Republicans come in.

One of the lawmakers who signed the letter, Jim DeMint, R-S.C., said recently that he may employ delaying tactics to hold up the treaty.