Libyan officials said today a Nato strike had hit a civilian house in the capital and killed several residents, an allegation which, if confirmed, could sow fresh doubts inside the alliance about its mission in Libya.
A Nato spokesman said the alliance was taking the reports of civilian casualties very seriously and it would try to establish if it was a Nato bomb which had killed the residents.
On another front in the four-month-old battle to force out Libyan leader Muammar Gadafy, a doctor in the city of Misrata said eight rebel fighters had been killed and 36 wounded in fighting with government troops.
In the early hours of this morning, reporters were taken by Libyan government officials to a residential area in Tripoli's Souq al-Juma district where they saw a body being pulled out of the rubble of a destroyed building.
Later, in a hospital, they were shown the bodies of a child and two others who, officials said, were among a total of seven people killed in the strike.
"There was intentional and deliberate targeting of the civilian houses," deputy foreign minister Khaled Kaim said at the site. "This is another sign of the brutality of the West."
There was no way for reporters to verify that all the bodies they were shown came from the building.
Libyan claims of civilian casualties from Nato attacks have sometimes been received sceptically by international media.
On one occasion, Libyan officials presented a wounded child as the victim of an air strike but medical staff passed a note to a foreign journalist saying she was hurt in a road accident.
"Nato would be very sorry indeed if the review of this incident concludes it to be a Nato weapon," Nato spokesman Wing Commander Mike Bracken told the BBC World Service.
"But I would ask that you look at our record during this operation over the last three months and the use of precision guided weapons to avoid civilian casualties."
If it is proved that the deaths were caused by a Nato air strike, it would be the first acknowledged incident of its kind in the campaign and could weaken the already fragile resolve of some countries in the alliance.
Nato has been pounding targets in Libya for months in what the alliance says is an operation to protect civilians who rebelled against Col Gadafy's 41-year rule.
Strains are appearing within Nato member states as the campaign drags on for longer than most of its backers anticipated and Gaddafi remains in power - even making a show of defiance last week by playing chess with a visiting official.
Rebels from the city of Misrata, about 200 km (130 miles) east of Tripoli, have been trying to push west towards the capital but today they took heavy casualties when they came under fire from pro-Gadafy forces.
A doctor at a field hospital near the front line in Dafniyah, an area just west of Misrata, said eight fighters had been killed and 36 wounded.
A Reuters reporter at the field hospital said he saw a procession of pick-up trucks arriving from the front carrying the wounded and the dead, some of them covered up with blankets.
"Gadafy's forces were underground (in trenches). We were patrolling and they ambushed us," said rebel fighter Mohammed Swelhi, whose friend, Mustafa, was one of two bodies brought from the front in the back of a truck.
"My cousin was injured yesterday. And today my friend was killed. My group, we're all close friends," he said.
Last week, Nato aircraft dropped leaflets around the front line warning pro-Gadafy fighters they would be targeted by attack helicopters if they did not lay down their arms. But rebels say there has been little sign of the alliance.
"We don't know what Nato is doing," said the doctor, called Nury, who was tending the wounded at the field hospital.
After four months of civil war, rebels control the eastern third of Libya, the Mediterranean port city of Misrata and much of the Western Mountains region stretching to the border with Tunisia.
But they remain far from seizing their ultimate prize - Col Gadafy's powerbase of Tripoli and its hinterland - despite air support from the world's most powerful military alliance.
Speaking in the eastern city of Benghazi, the chief rebel oil official castigated Western powers for failing to make good on their promises to help the rebel cause.
"We are running out of everything. It's a complete failure. Either they [Western nations] don't understand or they don't care. Nothing has materialised yet. And I really mean nothing," Ali Tarhouni said in an interview with Reuters.
"All of these people we talk to, all of these countries, at all these conferences, with their great grand speeches - we appreciate (them) ... but in terms of finances they are a complete failure. Our people are dying," he said.
Reuters