NATO's top official has arrived in Tripoli for talks with Libyan authorities on the final day of the alliance's seven-month bombing campaign that helped the former rebels drive Moammar Gadhafi from power.

Secretary-General Anders Fogh Rasmussen is holding talks Monday with Libya's National Transitional Council, including chairman Mustafa Abdel Jalil. His visit marks the first to Libya by a NATO secretary-general.

Rasmussen told the French news agency discussions will focus on Libya's expectations regarding possible future NATO assistance and the country's roadmap for a transition to democratic rule.

The alliance is set to end its mission in Libya at midnight Monday Libyan time after its air campaign to protect civilians under a U.N. Security Council resolution.

NATO formally decided to halt the mission after the U.N. canceled the mandate last week, though Libya's transitional leaders had urged NATO to continue until for a while because of security concerns.

U.S. Secretary of State Hillary Clinton says Libya faces a “huge challenge” to unify the country, and that leaders have a complicated political task ahead of them. But she told The Washington Post the United States and other countries have offered assistance, and will help Libya in any way they can.

Meanwhile, Libya's outgoing provisional prime minister, Mahmoud Jibril, confirmed Sunday the presence of chemical weapons in the country. He did not provide details on chemical weapons sites, but said representatives from international organizations are set to arrive later this week to take care of the issue.

Last week, the top U.N. envoy to Libya, Ian Martin, told the Security Council that previously undeclared chemical weapons sites had been found in Libya.

Provisional leaders declared the country liberated from the 42-year rule of Moammar Gadhafi during a ceremony on October 23. Officials have said they plan to form a new interim government within a month, followed by elections for a constitutional assembly within eight months. Parliamentary and presidential elections would be held within a year after that.