BENGHAZI, Libya — The Libyan rebel capital Benghazi was rocked by sustained gunfire and explosions overnight as fighters celebrated reports that Seif al-Arab, a son of Libyan strongman Muammar Gaddafi, died.

But by early Sunday doubts about the truth of the report crept in, quelling the joyful mood, as it was suspected that news of Seif al-Arab's death in a NATO air strike was propaganda from the Tripoli regime.

"I don't believe it because it was told by the Libyan TV," said Waleed Mohammed, 34, a policeman.

He added that if the news were true it would "not make the war finish early because Gaddafi is a crazy man," and "even if all his family were dead, he won't give up. Not until he dies."

A regime spokesman on Sunday said a NATO raid killed Gaddafi's second-youngest son and three grandchildren, but that the Libyan strongman had escaped unhurt.

But scepticism quickly replaced jubilation in the eastern rebel bastion, where a parallel government is gearing up to take the reins should Gaddafi be ousted or killed.

"I don't believe it because it is all on the Libya channels and that is all lies," said Mohammed Dahash, 25, who works in a mobile phone shop.

"I don't think it is true because since February 17 everything Gaddafi has said has been lies," said Ahmed Sidan, 20, evoking the start date of the anti-regime demonstrations that escalated into violent conflict.

"He did it before: in 1986 he said his daughter was killed but she is still alive," Sidan said of Kadhafi's claim that his adopted child, Hanna, was killed in an air raid ordered by then-US president Ronald Reagan.

"Kadhafi always lies," said Alsharifa Warfali, 48, a mother of seven.

"But if Seif is dead, so what? We've lost hundreds of sons in Benghazi. Gaddafi's son is not extra special," she added.

That sentiment was echoed in the higher echelons of the Libyan opposition Transitional National Council.

"We regret the spilling of any Libyan blood in the world... but the blood of Gaddafi's son is not more precious than that of the Libyan people," Mustafa Mohamed Abdul Jalil, chairman of the TNC, told Al-Jazeera television.

Very little is known about Gaddafi's youngest son, who made a splash in the German city of Munich in 2007 when he was involved in a night club brawl over a striptease show staged by his female dancing partner, Der Spiegel reported.

Libyan state television showed senior Muslim and Christian clerics "presenting their condolences" as they stood before four bodies covered by sheets.

And the Roman Catholic Bishop of Tripoli, Giovanni Martinelli, confirmed to an Italian television channel that Seif al-Arab had been killed.

But lack of material evidence to support reports of Seif al-Arab's death, which were aired on Libya's state-controlled channels, coupled with the absence of a confirmation from NATO, also fed mistrust among opposition media professionals.

"Gaddafi has said Seif is dead... so where is the body? Show us the body," said Alaa al-Obeidi, a producer for the Qatar-based channel Libya al-Ahrar.

"Personally, I don't think he is dead. He will get new IDs and passports to leave the country and go live in Africa, probably Uganda, which has good ties with Gaddafi," he added.

"Gaddafi is trying to milk NATO air strikes on military facilities to say they are trying to assassinate him," said Jalal al-Gallal, who serves on the media committee of the Benghazi-based TNC.

"But the truth is, the news cannot verified. There is no evidence, it is all hearsay," Gallal said, adding "if it is true, I hope Gaddafi will see the light and leave Libya to put an end to this bloodshed."

The Russian foreign ministry said on Sunday it had "serious doubts" the West was not targeting Libyan leader Gaddafi and his family.

But Libyan diplomat who defected from the regime said Gaddafi was a legitimate target for air strikes "because the only official function he had ever insisted in holding was that of highest commander of the Libyan army."

"That makes him a legitimate military target," Idris Tayeb Lamin, who says he was a political prisoner for 10 years before being pardoned by the regime without rhyme or reason, told AFP.

"This is the job Gaddafi insisted to have and it is the job that will get him killed," he said.

Asked why the mood had shifted from euphoria to scepticism overnight he said people were desperate for a reason -- any reason -- to celebrate as they had "adjourned their lives" waiting for a "bomb to land on Gaddafi's head."

"Libyans have become like prisoners waiting for someone to open the door... for Gaddafi to go," he said.