LONDON - Libyan Foreign Minister Moussa Koussa, one of Muammar Gadhafi's closest advisers and a former spy chief, defected and flew to Britain on Wednesday.

A British government source described his resignation as "a significant blow" to Gadhafi and Koussa's predecessor at the ministry said he was "part of the regime's spinal cord ... Koussa is a pillar of the temple".

Rebels sort anti-aircraft ammunition at a checkpoint west of Ajdabiyah, Libya, on Thursday. [Photo/Agencies]

The Libyan government has conceded that Koussa has resigned.

Government spokesman Moussa Ibrahim said on Thursday that Koussa's decision was personal and "other people will step in and do the job".

Ibrahim says Koussa had been given permission to go to Tunisia because he was sick with diabetes and high blood pressure but the government didn't know he would go to London.

Related readings:  Libyan foreign minister defects 'on his free will'  Britain doesn't rule out arming Libyan rebels  Questions remain over Libyan air strikes  Hu slams use of force, seeks Libyan ceasefire

He arrived in Britain on Wednesday on a flight from Tunisia.

China reiterated on Thursday the urgent need for a cease-fire and solve the Libya crisis through peaceful means.

"Given the current situation, we believe that it is urgent to stop armed conflicts and solve the Libya crisis as soon as possible with peaceful means," said Chinese Foreign Ministry spokeswoman Jiang Yu at a regular press briefing.

China supports the UN, the African Union, the League of Arab States and other international organizations playing an active role in addressing the Libya crisis politically.

"We believe that the affairs and future of Libya should be decided by Libyans themselves," she added.

Govt forces rebound

Government ground forces recaptured a strategic oil town and moved within striking distance of another major eastern city, nearly reversing the gains rebels made since international air strikes began. Rebels pleaded for more help, while a US official said government forces are making themselves harder to target by using civilian "battle wagons" with makeshift armaments instead of tanks.

At least 40 civilians have been killed in air strikes by Western forces on Tripoli, the top Vatican official in the Libyan capital told a Catholic news agency on Thursday citing witnesses.

"The so-called humanitarian raids have killed dozens of civilian victims in some neighborhoods of Tripoli," said Giovanni Innocenzo Martinelli, the Apostolic Vicar of Tripoli.

Western powers kept up the pressure to force Gadhafi out with new air strikes in other parts of Libya, hints that they may arm the opposition and intense negotiations behind the scenes to find a country to give a haven to Libya's leader of more than 40 years.

Also on Wednesday, an US official and a former US intelligence officer said that CIA operatives were sent to Libya this month after the agency's station in the capital was forced to close. CIA officers also assisted in rescuing one of two crew members of an F-15E Strike Eagle that crashed, they said. They spoke on condition of anonymity because of the sensitivity of the information.

Arms supply plan

A key member of the US Congress came out strongly on Wednesday against supplying arms to the rebels fighting Gadhafi, while Secretary of State Hillary Clinton said no decision had been made.

Mike Rogers, the Republican chairman of the US House of Representatives intelligence committee, declared his opposition to supplying arms to the rebels just before Clinton and three other senior US officials went to Capitol Hill to brief lawmakers about US military operations in Libya.

A number of US lawmakers have complained vociferously that they were not adequately consulted before the US joined in a multinational coalition conducting air strikes aimed at protecting civilian from attacks by Gadhafi's forces this month.

NATO in command

NATO finally took full command of all Libyan operations on Thursday, but only a minority of the 28 allied nations will conduct the bombings that had been under US leadership until now.

An armada of ships and warplanes from the United States, France, Britain, Canada and other coalition nations came under NATO control after the alliance overcame internal divisions to take over the mission.

"On Thursday morning, NATO took sole command of international air operations over Libya," said NATO Secretary-General Anders Fogh Rasmussen.

"In line with the mandate of United Nations Security Council Resolution 1973, NATO's focus is on protecting civilians and civilian-populated areas against the threat of attack," Rasmussen said.

Reuters-AP-Xinhua-AFP