At least 10 Nato strikes have hit in and around the Libyan capital, targeting military barracks close to Colonel Muammar Gaddafi's compound in central Tripoli, a police station and a military base, a government official said.
It was not immediately clear if there were any casualties.
The strikes appeared to be the heaviest in Tripoli since South African President Jacob Zuma visited Gaddafi earlier this week in an apparently unsuccessful effort to find a peaceful resolution to the country's crisis.
Meanwhile, a UN official said the world body's refugee agency would meet with a Libyan woman who claimed she was gang-raped by Gaddafi's troops. She was deported on Thursday from Qatar where she had sought refuge and was flown against her will to Benghazi, the official said. Benghazi is the Libyan rebels' de facto capital.
Speaking in Geneva, the official, Adrian Edwards, said his agency was with Iman el-Obeidi when she was taken from her Qatar hotel against her will. He said she is a recognised refugee, and her deportation violated international law.
US State Department spokesman Mark Toner said the US was "monitoring the situation" and working to ensure al-Obeidi's safety.
"We're concerned for her safety, given all that's happened to her. And we're going to work to make sure that she's kept safe, first and foremost, and that she finds appropriate asylum," Mr Toner told reporters in Washington on Thursday.
In March, al-Obeidi rushed into Tripoli's Rixos Hotel where all foreign correspondents are forced to stay while covering the part of Libya under Gaddafi's control, and shouted out her story of being stopped at a checkpoint, dragged away and gang-raped by soldiers. As she spoke emotionally and as photographers and reporters recorded her words, government minders, whose job is to escort reporters around the area, jumped her and dragged her away.
She disappeared for several days, then turned up in Tunisia and later Qatar. She was heard from little until Thursday, when she was suddenly expelled from Qatar and ended up in Benghazi. No explanation was forthcoming from Qatar.
Rebel spokesman Jalal el-Gallal said al-Obeidi arrived in Benghazi by plane. "She's welcome to stay, this is her country," he said.
Libyan authorities have alternately labeled al-Obeidi a drunk, a prostitute and a thief.
Al-Obeidi has maintained that she was targeted by Gaddafi's troops because she is from Benghazi, the rebel stronghold. Her rape claim could not be independently verified.
Human rights violations are one aspect of the rebels' complaints against the Gaddafi regime. This week a report by a UN body said it found evidence of war crimes and crimes against humanity by Gaddafi's government, and also charged that the rebels have committed abuses.
The Chinese Foreign Ministry said that China's ambassador to Qatar recently met with the head of Libya's rebel council, the first known meeting between the two sides. China abstained in the UN Security Council vote authorizing Nato military action in Libya.