The Bush administration on Friday welcomed a new South Korean leader bringing tough talk on North Korea and an apparent resolution to a dispute over U.S. beef that had blocked an ambitious free trade deal.

President Bush and President Lee Myung-bak, in two days of talks beginning Friday, will be eager to signal a cooperative tone as they push a reluctant Congress to ratify the trade deal and discuss ways to persuade North Korea to fulfill its commitments in six-nation nuclear negotiations.

The beef ban is the main obstacle to an accord to slash tariffs and other barriers to trade that the two countries signed last year after long negotiations. The U.S. has demanded that Seoul fully open its beef market, saying that is needed for congressional leaders in Washington to back the accord.

The South Korean Agriculture Ministry said Seoul would allow U.S. beef imports from cattle younger than 30 months. Younger cows are believed to be less at risk for mad cow disease. South Korea said it would allow beef from older cattle after the U.S. strengthens controls on feed to reduce chances of infection.

But even with progress on beef, the trade deal could face trouble as U.S. lawmakers, including Democratic presidential candidates Hillary Rodham Clinton and Barack Obama, voice increasingly anti-free trade sentiments.

Lee on Friday met with Secretary of State Condoleezza Rice and with U.S. trade envoy Susan Schwab. Schwab released a statement saying that the resumption of U.S. beef exports to South Korea removes the major obstacle to congressional consideration of the deal. Schwab said that "safe, affordable, high-quality American beef will soon be back on Korean tables."

But the office of Sen. Max Baucus, the Democratic head of the Senate Finance Committee, said in a statement that Baucus is blocking consideration of the trade agreement "until all cuts of U.S. beef from cattle of all ages are on Korean store shelves."

"Korea must provide full market access for all U.S. beef, and I believe this deal can get us there if the Korean government follows through," Baucus said. "I will closely monitor the implementation of this new import protocol, and I expect great results."

With only nine months left in Bush's presidency, and with the North Korean nuclear talks at an impasse, it may be too late for the leaders to settle another top foreign policy goal for the Bush administration: a deal to rid North Korea of its atomic bombs.

Lee, a former construction chief executive nicknamed "The Bulldozer" for his determination to get things done, has ended a decade of liberal rule in which South Korea sought to embrace the North and refrained from criticism. The relief in Washington has been evident in the Bush administration's praise of Lee's insistence that the North follow through on nuclear pledges before receiving aid from its southern rival.

Lee's position on North Korea may turn out to be even tougher than Bush's because the United States is pressing hard for an agreement. Nuclear talks are stalled over whether the North will hand over a promised full declaration of its nuclear programs in return for concessions. The Bush administration apparently has decided that the declaration's exact contents are less important than an assurance that the nuclear negotiators can check up on Kim Jong Il's government to make sure it has told the truth.

This has prompted skepticism even from within Bush's own party.

Rep. Ed Royce, the top Republican on the House Foreign Affairs terrorism, nonproliferation and trade subcommittee, said he raised the need to verify any North Korean actions in a meeting Thursday with Lee. "Congress is carefully watching the six-party talks, and solid verification is a must if the process is to move forward," Royce said in an interview.

While taking a harder line with the North, Lee also will propose creating a permanent high-level diplomatic channel between North Korea and South Korea, including establishing the first liaison offices in the nations' capitals after nearly six decades of division, The Washington Post reported in Friday editions.

The highlight of Lee's Washington visit will come when he is feted at the Camp David presidential retreat in mountains north of the U.S. capital, where he was to stay overnight Friday.