Several U.S. lawmakers are protesting recent moves to resume U.S.-North Korea dialogue and the six-party nuclear talks.

Senate Republican Whip Jon Kyl, Senator John McCain and Senate Homeland Security committee chairman Joseph Lieberman sent a letter to Secretary of State Hillary Clinton last week.

In the letter, they urged that the six-way talks not be resumed until North Korea takes detailed steps to improve ties with South Korea and until it demonstrates a commitment to complete, verifiable and irrevocable denuclearization.

Kyl and McCain are key members of the Senate Republican leadership. Lieberman is an Independent heavyweight who was the Democratic vice presidential candidate in the 2000 election.