U.S. President George Bush says North Korea must abide by terms of an international agreement aimed at ending its nuclear program. VOA White House Correspondent Scott Stearns reports, the White House is defending the deal reached Tuesday in Beijing.

President Bush telephoned Chinese President Hu Jintao Thursday to congratulate him on China's role in reaching the deal. White House officials say he told the Chinese leader that it is now up to North Korean leader Kim Jong Il to live up to its terms.

Pyongyang has agreed to shut down and seal its primary nuclear facilities within 60 days and allow inspectors to verify the process. In exchange, North Korea will receive 50,000 tons of heavy fuel oil from South Korea.

Once it discloses and verifiably abandons all of its nuclear programs, the deal says, North Korea will receive additional economic, humanitarian and energy assistance.

The agreement has been criticized by some of President Bush's political opponents for being no better than a deal that could have been struck four years ago, before North Korea tested a nuclear bomb.

It has also been criticized by some of the president's political supporters for being too accommodating to Pyongyang by easing financial pressures.

The politically conservative editorial page of The Wall Street Journal described the deal as "something close to faith-based nonproliferation."

White House Spokesman Tony Snow says that is not so.

"What we have done is put together an agreement that in fact is not faith-based," he said. "It is performance-based. And that is the most important thing to understand. The North Koreans don't get anything for free."

Snow says the White House and State Department are working to better explain the plan. Even within the administration.

One of the president's deputy national security advisers, Elliot Abrams, sent a series of e-mails questioning a provision that says the United States will begin the process of removing North Korea from a list of state sponsors of terrorism.

Snow says Abrams' concerns have been satisfied.

"He had the same concerns that many people have had, which is, 'Is this a political deal? Are you trying to offer a political deal to the North Koreans, saying that, 'if you come to the table, all is forgiven, we will de-list you?'' And the answer is no," he said.

The president's former U.N. ambassador, John Bolton, says it is a bad, disappointing deal that contradicts fundamental premises of Washington's previous approach to North Korea.

President Bush Wednesday told White House reporters that he strongly disagrees with Bolton. Those who believe it is not a good deal, Mr. Bush says, are flat wrong.

"This is a phased approach that will enable all of us to say to our respective populations: 'We are watching carefully, and there is an opportunity for the North Koreans to prove that this program can work,'" he said.

The deal is backed by a U.N. Security Council resolution that retains economic sanctions. In his phone call with President Hu, White House officials say, President Bush emphasized the need to fully implement that resolution, which was imposed after North Korea's nuclear test in October.