WASHINGTON — The Bush administration announced on Saturday that it was removing North Korea from a list of state sponsors of terrorism and said the country had agreed to adhere to concessions on its nuclear program, in a bid to salvage a fragile nuclear deal that seemed on the verge of collapse.

Sean McCormack, the State Department spokesman, said the key to the diplomatic shift, after weeks of tense negotiation, was North Korea's agreement to resume disabling its plutonium plant at Yongbyon, replace the seals on its nuclear equipment and allow international inspectors to return.

But almost immediately, the move brought expressions of concern from Republican lawmakers, including the presidential nominee, Sen. John McCain.

In the most significant part of the agreement, North Korea agreed to a verification regime that would allow U.S. inspectors access to all of its declared nuclear facilities. But according to a senior administration official, the deal puts off decisions on the thorniest verification issue: what happens if international experts suspect the North is hiding other nuclear weapons facilities.

The United States wanted the North to agree to inspections at sites that raise suspicions, but North Korea balked. The new agreement calls for U.S. inspectors to be granted access "based on mutual consent" with North Korea.

Experts on North Korea say that the concession by the United States was probably necessary to achieve a deal, but that it no doubt will lead to more fights, since the North's leaders will not want to give inspectors free rein to travel the country.

McCain said in a statement that he wouldn't support the deal until he got some questions answered. "I expect the administration to explain exactly how this new verification agreement advances American interests and those of our allies before I will be able to support any decision to remove North Korea from the list of state sponsors of terrorism," he said. He added that he was "concerned that this latest agreement appears to have been reached between Washington and Pyongyang, and only then discussed with our Asian allies in an effort to garner their support."