Loud explosions have been heard in the Libyan capital Tripoli as jets flew over the city, witnesses said.
A Reuters correspondent heard four explosions in Tripoli as jets flew overhead on two occasions on Saturday. The blasts appeared to come from the eastern suburb of Tajura.
Libyan state TV had earlier reported that at least 15 people were killed in strikes on civilian sites in the eastern city of Brega, a claim promptly denied by NATO.
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"The colonialist crusader Atlantic coalition bombed civilian sites, among them a bakery and a restaurant in Brega, creating 15 martyrs and more than 20 wounded, among them regular clients of those places," state TV reported.
The report, which did not say when the attack took place, referred to a NATO "war of extermination" and "crimes against humanity" in Libya.
However, state news agency Jana said the attack was on Saturday and spoke of five more "citizens" killed a day earlier.
Following the Libyan television claim, the NATO spokesman said the alliance "did target buildings in an abandoned area of Brega".
"These were legitimate military targets that were hit We took a long time to watch the area and make sure. Meticulous planning went into this."
As far as NATO is concerned, he said, "any people in that area at that time were legitimate military targets."
In its daily operations report, the alliance said that on Friday it had targeted 35 objectives, including military vehicles and installations, around Brega, a key refinery town some 800km east of Tripoli and 240km southwest of the rebel stronghold of Benghazi.
Earlier this week, after NATO admitted misfires that Tripoli says caused several deaths, Italian Foreign Minister Franco Frattini called for a suspension in the campaign in the latest sign of dissent within NATO.
"I believe an immediate humanitarian suspension of hostilities is required in order to create effective humanitarian corridors," while negotiations should also continue on a more formal ceasefire and peace talks, he said.
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NATO chief Anders Fogh Rasmussen said more civilians would die if operations were not maintained under a UN mandate to protect Libyans from the exactions of the government of veteran leader Muammar Gaddafi.
"NATO will continue this mission because if we stop, countless more civilians could lose their lives," Rasmussen said in a video statement on the NATO website.
In rebel-held Misurata, 200km east of Tripoli, a rebel spokesman called Abdelsalam said Gaddafi's forces shelled the city but that things were quieter since a NATO strike on Wednesday which took out pro-Gaddafi positions.
A local doctor said there had been no serious injuries.
A top rebel official, citing the existence of talks with Gaddafi allies through intermediaries, said they would be ready to discuss any political settlement that did not involve Gaddafi remaining in power, but said no proposals had emerged as yet.
Abdel Hafiz Ghoga, vice chairman of the rebel National Transitional Council (NTC), recognised by about 20 countries as the legitimate representatives of the Libyan people, reiterated that a political settlement was possible.
"We have agreed to take a serious look at any proposal as long as Gaddafi does not remain in power. We are waiting for any proposals that are (being discussed) around the world," he told reporters in the eastern rebel stronghold of Benghazi.
"We have not received anything yet," he added. Officials for Gaddafi's government in Tripoli were not immediately available to comment.
Meanwhile, 17 of the country's top players, including national goalkeeper Juma Gtat, have defected to rebels, the BBC reported.
Adel bin Issa, the coach of Tripoli's top club al-Ahly, announced the defections in the rebel-held Nafusa Mountains in western Libya.
"I am telling Colonel Gaddafi to leave us alone and allow us to create a free Libya," the BBC quoted Gtat as saying at a hotel in the town of Jadu.
"In fact I wish he would leave this life altogether."
Gaddafi has suffered a series of defections by military officers, diplomats and members of his government, but has resisted efforts by rebels backed by a NATO bombing campaign to dislodge him after four decades in power.