A Syrian television station has aired an audio message purportedly from ousted Libyan leader Moammar Gadhafi, who slammed reports that he had fled Libya in a convoy to neighboring Niger.

In the comments broadcast Thursday on Al-Rai TV, Mr. Gadhafi called the reports “lies” designed to destroy morale and insisted he is still in Libya. He said his supporters will defeat NATO and are ready to fight transitional authority forces in the capital, Tripoli.

The National Transitional Council has sent envoys to Niger in an effort to prevent Mr. Gadhafi and his entourage from escaping justice by fleeing across the border. Mr. Gadhafi's whereabouts are not known, and Niger's government has confirmed the former strongman is not in the country.

Officials in Niger say they are acting in consultation with the NTC and that recent movements of Libyan convoys across the border have been much smaller than reported.

Meanwhile, U.N. Secretary-General Ban Ki-moon said Thursday the transition process in Libya cannot move backwards, and the United Nations will continue to help the Libyan people reach their aspirations of human rights and democracy.

The U.S. Ambassador the United Nations, Susan Rice, said Wednesday the Security Council expects a briefing in the coming days from the U.N.'s special representative for post-conflict planning in Libya.

Rice said a draft resolution will then be crafted based on the report, showing the Council's “support and approval” for steps the U.N. plans to take to put its personnel to work in Libya. She said those actions would be consistent with requests from the NTC, and that the Council will also review the sanctions currently in place against Libya in light of recent developments.

In Washington, the State Department said U.S. officials have urged North African countries to tighten border controls, arrest fleeing Gadhafi government officials and impound funds they may be carrying. Spokeswoman Victoria Nuland acknowledged that news reports about large convoys crossing Libya's southwest frontier were “overblown.”

Niger Justice Minister Marou Amadou said Wednesday a total of 18 people – including five Niger citizens – in four vehicles had entered the country from Libya in recent days. He said there was no convoy of 200 vehicles, as had been reported by some media.

Other Niger officials confirmed that senior members of Mr. Gadhafi's government – led by his own security chief, Mansour Dhao – had crossed the border together with Tuareg fighters from Niger who had joined the former leader's forces.

NATO said Thursday its warplanes bombed five armored vehicles near Mr. Gadhafi's hometown, Sirte, as well as 18 surface-to-air missile systems around the town of Waddan about 300 kilometers to the south.

In the desert outpost of Bani Walid, negotiators from Libya's National Transitional Council say they are committed to avoiding bloodshed where they are pressing tribal elders tied to Mr. Gadhafi's former rule to surrender.

Town elders and NTC representatives met Tuesday for talks at a mosque on the town's outskirts, but the elders were later confronted by angry citizens, including Gadhafi supporters, who fired into the air and sent them fleeing.