Speaking to reporters late Thursday, Ibrahim said the offer was the furthest the government had gone since fighting broke out against rebels seeking to overthrow the Libyan regime led by Muammar Gaddafi.

He said as part of the deal, NATO would also have to halt its strikes of Libyan targets.

There was no immediate comment by rebel leaders based in the eastern city of Benghazi.

Speaking at a press conference on Thursday, Ibrahim also said NATO air strikes targeted the port of the Libyan capital Tripoli on Thursday night.

"I have just learned that the port of Tripoli is now being targeted by NATO air raids. I am told that a boat has been hit," Ibrahim said, without giving further details on the ship.

Witnesses told Agence France-Presse that they heard at least four explosions in the port and saw columns of smoke rising from the area.

"Military and civilian sites are currently the targets of raids by the colonialist Crusader aggressor," Libyan state television said.

Tripoli is targeted nearly daily with air raids by the international coalition, which launched strikes on March 19 to prevent Gaddafi's forces from attacking civilians.

NATO took over command of the operation on March 31.

Meanwhile, Libyan state television on Thursday showed footage of strongman Gaddafi holding talks with a senior official apparently back from a mission to Moscow this week.

Gaddafi, who appeared in good health and spirits, was seen holding discussions with Mohammed Ahmed al-Sharif, who held talks in the Russian capital on Tuesday with Foreign Minister Sergei Lavrov.

The broadcast showed Gaddafi and Sharif holding talks in an office where a television screen in the background flashed a program and a green ticker that read: "Thursday May 19, 2011."

Gaddafi was dressed in black and wearing his trademark sunglasses.

NATO-led jets have repeatedly targeted Gaddafi's Bab al-Aziziya headquarters in Tripoli in recent weeks.

Rumours last week suggested that the Libyan leader had been wounded in one such attack.

Gaddafi denied the claim and said in an audio message broadcast on state television on May 13 that he was in a place where NATO bombs cannot reach him.

"I want to say to the Crusader cowards that I live in a place where I cannot be reached or killed; I live in the hearts of millions," Gaddafi said in the message.