North Korea has agreed to disable all of its nuclear facilities by the end of the year, in a move that the Bush administration hailed as a diplomatic victory that could serve as a model for how to deal with Iran, which has defied American efforts to rein in its nuclear ambitions.

The North Korea agreement, announced in Beijing on Wednesday, sets out the first specific timetable for the North to disclose all its nuclear programs and disable all facilities in return for 950,000 metric tons of fuel oil or its equivalent in economic aid.

The accord is the second stage of a six-nation pact reached in February, one that has continued to draw sharp criticism from conservatives who complain that the United States is rewarding North Korea for its test of a nuclear device last October. The agreement has not yet resolved the contentious question of when North Korea will give up its nuclear weapons.

The agreement calls on the United States to "begin the process of removing" North Korea from a United States terrorism list "in parallel" with the North's actions. Conservative critics said the United States should not take North Korea off the terrorism list until it gave up all its nuclear weapons, and argued that the pact was far too conciliatory toward a nuclear power with alleged ties to international terrorism.

But the Bush administration has been eager to show diplomatic progress, and Bush suggested that the deal should serve as an example to Iran, which has refused to suspend its uranium enrichment program. During a town hall meeting on Wednesday in Lancaster, Pennsylvania, Bush told a questioner that he might hold direct talks with Iran if it first froze enrichment of uranium.