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By Jessica Donati and Mark Felsenthal

KABUL/WASHINGTON, Nov 26 (Reuters) - Afghanistan and the United States appeared even farther from a deal on Tuesday that would allow U.S. troops to remain in Afghanistan after 2014 as a meeting between President Hamid Karzai and a senior U.S. official revealed new differences over the controversial agreement.

Afghan President Hamid Karzai told U.S. National Security Advisor Susan Rice, who met with the Afghan leader on Monday during a visit to Kabul, that the United States must put an immediate end to military raids on Afghan homes and demonstrate its commitment to peace talks before the Afghan leader would sign a bilateral security pact, Karzai's spokesman said.

The White House said that Karzai had outlined new conditions in the meeting on Monday with Rice and "indicated he is not prepared to sign the (bilateral security agreement) promptly," a White House statement said.

The latest obstacle to concluding the long negotiations on the security agreement is unwelcome news for the Obama administration a day after an assembly of Afghan elders endorsed the deal, but Karzai suggested he might not sign it until after national elections next spring.

It also deepens questions about whether any U.S. and NATO troops will remain after the end of next year in Afghanistan, which faces a still-potent insurgency and is still training up its own military.

U.S. officials, including Secretary of State John Kerry and Defense Secretary Chuck Hagel, said the deal must be signed by year-end to begin preparations for a post-2014 presence.

Rice, who made a three-day visit to Afghanistan to visit U.S. troops, told Karzai that the delay "would not provide the United States and NATO allies the clarity necessary to plan for a potential post-2014 military presence," the White House said.

"Without a prompt signature, the U.S. would have no choice but to initiate planning for a post-2014 future in which there would be no U.S. or NATO troop presence in Afghanistan," the statement said.

There are currently 47,000 U.S. troops in Afghanistan.

CONDITIONS

Karzai spokesman Aimal Faizi said the Afghan leader laid out several pre-conditions for his signature to the deal in the meeting, including a U.S. pledge to halt all military raids on, or searches of, Afghan homes immediately.

The Bilateral Security Agreement (BSA) includes a provision allowing raids in exceptional circumstances - when an American life is directly under threat - but it would not take effect until 2015.

This issue is particularly sensitive among Afghans after a dozen years of war between Afghan and foreign forces and Taliban militants.