A senior Democratic congressman plans to go to Libya this weekend at the invitation of Muammar al-Qaddafi (search) to check on the Libyan leader's pledge to dismantle his nation's nuclear weapons program.

Rep. Tom Lantos (search), D-Calif., will meet with Libyan officials and possibly al-Qaddafi, whose decision to halt development of weapons of mass destruction marked a major policy shift by the North African leader.

Lantos, senior Democrat on the House International Relations Committee, will report his findings to Congress and to the Bush administration, his office said in a statement announcing the trip.

A separate congressional group headed by Rep. Curt Weldon (search), R-Pa., is going to Libya, as well.

The visits signal a growing momentum to repair U.S. relations with Libya, although the administration has taken no action to remove Libya from its list of countries that support terrorism or to lift the economic sanctions the listing requires.

Through a third party, Libya also has had preliminary discussions with Israel, a longtime foe.

Lantos discussed his trip with William Burns, the assistant secretary of state for the Near East, in Lantos' office on Wednesday.

Meanwhile, the State Department praised Libya as cooperating with U.S. and British experts as the country begins dismantling its nuclear weapons program.

A U.S. team has arrived and Libya is "facilitating its work," said State Department deputy spokesman Adam Ereli. Libya's invitation and cooperation are positive indicators, he said.

At the same time, Ereli said he did not have any details of what the U.S. and British experts had done so far.