WASHINGTON - President Bush, directly engaging the man he publicly called a "tyrant," wrote a letter to North Korea's leader, Kim Jong-il, in which he held out the prospect of normalized relations with the United States if North Korea fully discloses its nuclear programs and dismantles its nuclear reactor, administration officials said yesterday.

The high-level personal missive from Bush to the leader of the country he placed in his "axis of evil" in 2002 was sent as U.S. negotiators are struggling to get the secretive North Korean government to fully explain and disclose the extent, use and spread of its nuclear material and technology.

At the same time, the United States is also urging other nations to maintain pressure on Iran in the wake of a new assessment that Tehran halted nuclear weapons work in 2003.

Bush began with the salutation "Dear Mr. Chairman," and urged the enigmatic North Korean leader to reveal all of his country's past and present nuclear work.

"I want to emphasize that the declaration must be complete and accurate if we are to continue our progress," the letter said, according to a senior administration official.

The letter's very existence underscores just how much the White House wants to ensure that one of the administration's scarce, tangible diplomatic accomplishments does not slip away.

North Korea agreed in October to dismantle all of its nuclear facilities and to disclose all of its past and present nuclear programs by the end of the year in return for 950,000 metric tons of fuel oil or its equivalent in economic aid.

That agreement has come under criticism from national security hawks, but many foreign policy experts point to it as a rare diplomatic success in a period that has been dominated by frustration in Iran, the Middle East and Pakistan.

An administration official said that the letter flags the need to resolve three sticking points: the number of warheads North Korea built, the amount of weapons-grade nuclear material it produced and the need for North Korea to disclose what nuclear material and knowledge it has received from other countries and what nuclear material and knowledge it has passed on to other countries.

The letter to Kim Jong-il is dated Dec. 1, administration officials said. It was delivered it to a North Korean diplomat in Beijing on Wednesday.

_ Yesterday in Brussels, meanwhile, Secretary of State Condoleezza Rice won support from European allies for new U.N. sanctions against Iran over its nuclear program. *