Nato's secretary general today admitted that an alliance air strike was responsible for an attack on a suburb of Tripoli which killed nine civilians, according to Libyan officials.
Anders Fogh Rasmussen said Nato "deeply regrets" the incident, which he said was caused by an accident during air strikes designed to protect civilians against the forces of dictator Muammar Gaddafi.
Mr Rasmussen insisted that Nato would not be deflected from its mission to impose United Nations Security Council resolution 1973, adding: "We will stay committed as long as it takes."
He said there was "no solely military solution" to the crisis in Libya, and called for a political process to establish a future for the north African country, which would have to involve Gaddafi's removal.
A statement posted on the Nato website said a "weapons system failure" may have been responsible for a missile going astray in the early hours of yesterday.
Nato did not disclose which country's aircraft were involved, although the Ministry of Defence said RAF warplanes were not operating in the area at the time.
Mr Rasmussen told BBC Radio 4's World at One: "Unfortunately, it was an accident caused by one of our strikes."
He added: "We do our best to avoid civilian casualties but unfortunately sometimes accidents happen. We deeply regret this loss of civilian life and I convey my condolences to the bereaved families."
Confirmation that Nato aircraft were responsible for yesterday's deaths is a severe setback for the alliance, which has been at pains to avoid civilian casualties.
Libyan officials were swift to exploit the propaganda potential, with foreign minister Abdul Ati al-Obeidi calling for a "global jihad" on the West in response.
Journalists based in Tripoli were rushed to see the bomb-damaged building, which appeared to have been partially under construction.
Reporters were later escorted back to the site during daylight, where it was reported that children's toys, teacups and dust-covered mattresses could be seen amid the rubble.
Mr Al-Obeidi claimed that nine civilians, including two children, had been killed and 18 people wounded in the explosion.
He denounced the bombing as a "deliberate attack on a civilian neighbourhood".
"The deliberate bombing... is a direct call for all free peoples of the world and for all Muslims to initiate a global jihad against the oppressive, criminal West and never to allow such criminal organisations as Nato to decide the future of other independent and sovereign nations," he said.
Mr Rasmussen told the BBC that Nato forces - including RAF Typhoon and Tornado jets based in Italy - have flown 11,000 sorties since the start of operations in March, of which 4,000 have included air strikes.
Some 2,000 "important military targets" have been destroyed, while Nato has been "very successful" in avoiding civilian deaths, he said.
"We will stay committed as long as it takes to accomplish our mission - that is to fully implement the UN mandate to protect civilians in Libya," he added.
The Nato mission was recently extended to the end of September, but Mr Rasmussen denied suggestions that a stalemate had developed.
"We have considerably degraded (Gaddafi's) military capacity," said the Nato chief. "We see the opposition forces advance in Libya, we see people defect from his inner circle and internationally the Gaddafi regime is more and more isolated every day.
"All of that will eventually lead to the collapse of the regime. Time is out for Gaddafi and his regime."
However, he acknowledged: "Obviously, there is no solely military solution to the conflict in Libya. We need a political process and, as part of that, Gaddafi must go.
"It is hard to imagine a complete end to attacks against the civilian population as long as Gaddafi remains in power.
"We have defined three very clear military objectives for our operations: a complete end to all attacks against civilians, the withdrawal of Gaddafi forces to their bases, and immediate and unhindered humanitarian access.
"We will continue our operation until those objectives are met."Reuse content