NATO wants the United Nations to play the leading role into Libya's transition to democracy once leader Muammar Gaddafi steps down, the military alliance's secretary general said on Tuesday.

Speaking at a news conference in St. Petersburg, Anders Fogh Rasmussen said NATO "would like the UN to head the efforts that will help the Libyan people during the transition to democracy."

He added that "there should be no security vacuum during this period and the process should be all-embracing."

Rasmussen reiterated that the conflict in Libya needs a political resolution and Gaddafi must resign from his post.

"It is clear that there cannot be a one and only possible military solution in Libya. A political solution is needed, of course," he said.

"Libyan leader Muammar Gaddafi's exit has no alternative. Gaddafi must step down and satisfy the people's legitimate aspirations."

Libya has been rocked by fighting between pro- and anti-government forces since mid-February. The international military operation began on March 19 following a UN resolution and was extended until late September.

UN Security Council Resolution 1970, passed in February, prohibited states from providing any kind of arms to Libya. Resolution 1973, passed a month later, authorized countries "to take all necessary measures" to help protect Libyan civilians.