US President Barack Obama said Wednesday he was "confident" that a landmark nuclear arms treaty with Russia would be voted on by US lawmakers before the Christmas break.

Obama said he thought the new Strategic Arms Reduction Treaty (START), which he wants ratified by the end of the year, would be voted on before the US Senate goes into recess in the coming weeks.

"I am confident that we're going to be able to get the START treaty on the floor, debated and completed before we break for the holidays," Obama said after White House talks with Polish President Bronislaw Komorowski.

Komorowski, for his part, also called for ratification of the new START treaty, calling it an "investment in a better and safer future."

Earlier, Senate Foreign Affairs committee chairman John Kerry said lawmakers were "trying to work out whatever the best thing is."

"It's really a question of the overall Senate schedule. We're trying to work through when the tax bill would come, there's a lot going on," Kerry said after talks with number-two Senate Republican Jon Kyl.

The agreement, a key part of Obama's efforts to "reset" relations with Moscow, restricts each country to 1,550 deployed warheads -- a cut of about 30 percent from a limit set in 2002 -- and 800 launchers and bombers.

The agreement, which has broad US public support, would also return US inspectors who have been unable to monitor Russia's arsenal since the agreement's predecessor lapsed in December 2009.

The Russian lower house of parliament, the State Duma, has indicated it will ratify the treaty only after its ratification by the US Senate.

Russian Prime Minister Vladimir Putin warned in an interview with CNN television last week that Moscow would likely build up its arsenal if the accord fails.

But the treaty needs the support of more than two-thirds of the US Senate in order to pass.

The 100-seat Senate currently counts 56 Democrats and two independents who vote with them. Republicans hold 42 seats now, but that number will rise to 47 when the newly elected Congress arrives in January.

Kyl had earlier pledged to block action on the accord this year, demanding further assurances that US nuclear weapons would be modernized.

The White House has worked for months to ease what Republicans say are their concerns: That the treaty may handcuff US missile defense plans, and that more money is needed to keep the US nuclear arsenal up to date.

It has enlisted support from heavyweight politicians, including former president George H.W. Bush, who released a statement Wednesday urging ratification of the treaty.

His son, former president George W. Bush, has been silent on the issue.

Former US secretary of state Colin Powell, a veteran of 25 years of nuclear arms control pacts between Moscow and Washington, also has endorsed the new START treaty.

He stressed "the world has benefited by having fewer of these horrible weapons in existence, and we hope that we can continue this process."

It is not entirely clear when Senate Majority Leader Harry Reid will call the Christmas holiday recess, but most senators hope to be able to leave for their home states well before Christmas Eve, on December 24.