A convoy of at least 200 vehicles carrying forces loyal to Libya's Moammar Gadhafi has crossed into neighboring Niger, as anti-Gadhafi fighters continue to mass outside one of the ousted leader's last strongholds.

The U.S. State Department confirmed Tuesday that military vehicles carrying a dozen or more senior military leaders from Mr. Gadhafi's government are heading toward the capital, Niamey, after moving into Niger late Monday. The capital is in the country's southwestern corner near Burkina Faso, where officials offered Mr. Gadhafi asylum about two weeks ago.

State Department spokeswoman Victoria Nuland says the U.S. does not believe Mr. Gadhafi is in the convoy. News agencies quote Niger's foreign minister who denied reports that Mr. Gadhafi is traveling in one of the vehicles.

Nuland said the U.S. ambassador to Niger spoke to someone in the foreign ministry and believes the government of Niger will take appropriate measures to respond to the international community and work with Libya's National Transitional Council. She also urged the government of Niger to impound any property that belongs to the people of Libya.

Mr. Gadhafi's whereabouts are still unknown. It is not clear whether any of his relatives or officials from his government are among those who entered Niger, or whether they might join the convoy later.

The head of Mr. Gadhafi's security brigades, Mansour Dhao, and several other Libyans crossed into Niger hours ahead of the convoy. The Associated Press quotes a customs official as saying Dhao entered the Nigerian capital early Tuesday.

Meanwhile, more anti-Gadhafi reinforcements have joined thousands of fighters outside the Libyan city of Bani Walid, ahead of a Saturday deadline for pro-Gadhafi holdouts to surrender.

Negotiators for Libya's provisional authorities restarted talks Tuesday with tribal elders and pro-Gadhafi forces from Bani Walid, one of three remaining bastions of the ousted leader. The two sides met at a mosque on the town's outskirts, where representatives of Libya's NTC assured citizens of their safety and told the elders there would be “no revenge.”

The city is dominated by Libya's largest tribe, the Warfalla, which helped anchor Mr. Gadhafi's nearly 42-year rule. However, many of the anti-Gadhafi fighters encircling Bani Walid also are Warfalla members.

Officials from the NTC say at least two of the former leader's sons took refuge in the city in recent days. Mr. Gadhafi's spokesman, Moussa Ibrahim, is still believed to be there, but the former leader's most prominent son, Seif al-Islam Gadhafi, was reported to have fled Bani Walid for the southern deserts.

The NTC is focused on the city, about 170 kilometers southeast of Tripoli, because witnesses last saw members of Mr. Gadhafi's inner circle fleeing there.

While officials in Burkina Faso have offered refuge to Mr. Gadhafi, they also have recognized the NTC as the legitimate government of the Libyan people.