Libyan authorities accused NATO of killing 15 people in an airstrike Saturday that they said hit a restaurant and bakery in the east, though the alliance denied the report.
It was the latest outcry from Libyan leader Moammar Gadhafi's government blaming NATO for killing civilians amid a four-month uprising that has sparked a civil war. NATO insists it does all it can to avoid such casualties.
Meanwhile, rebel representatives said their fighters were coordinating around the country for the "zero hour" when their forces would reach the capital of Tripoli.
The rebels said they have been working to cut fuel supplies from the Tunisian border in an attempt to paralyze Gadhafi's forces. Rebels also are making homemade bombs and trying to ferry other weapons to their comrades in Tripoli, a spokesman for an underground guerrilla group there said.
Libya's state news agency quoted a military official in Gadhafi's forces as saying that NATO warplanes hit a number of civilian sites Saturday in the oil town of Brega, including a restaurant and a bakery.
The official said 15 civilians were killed and 20 wounded in the strike. The JANA news agency also claimed five civilians were killed Friday in Brega as well.
NATO said it did not carry out any strikes in the area on Saturday.
A NATO official said alliance warplanes did hit several targets in the vicinity of Brega on Friday but that there was no evidence civilians had been killed or wounded.
"We have no indications of any civilian casualties in connection with these strikes," said the official, who spoke on condition on anonymity because he was not authorized to speak to the media on the record. "What we know is that the buildings we hit were occupied and used by pro-Gadhafi forces to direct attacks against civilians around Ajdabiya."
Ajdabiya is a city between Brega and the rebel stronghold of Benghazi to the northeast.
NATO said it hit multiple military command sites Friday near Brega, which has been a frequent flashpoint between rebels and Gadhafi's forces.
The alliance said government forces had moved into buildings in an abandoned area of Brega and started using them as military compounds to launch strikes on civilians, putting rebel-held cities such as Ajdabiya and Benghazi at risk.
Reports of civilian casualties in NATO strikes have provoked intense anger among many Libyans in the west of the country under Gadhafi's control.
Images of dead civilians, including young children, described by the government as "martyrs," can be seen frequently at pro-government rallies and on state-controlled television.
NATO is investigating whether one of its airstrikes may have slammed into a civilian neighborhood in Tripoli on June 19, killing several civilians.
A day later, alliance warplanes struck a family compound belonging to a close Gadhafi aide, killing what the Libyan government says was 19 people, including at least three children. NATO called the site was a "command and control" center, and said it regrets any civilian deaths that resulted from the strike.
Rebel spokesman Abdel-Hafidh Ghoga in Benghazi said Gadhafi was to blame for civilian casualties in the fighting because "he keeps his weapons in highly populated civilian areas."
At least two explosions could be heard in the capital of Tripoli on Saturday, though it was not immediately clear what the NATO airstrikes may have hit.
The Libyan rebels began their uprising in February against Gadhafi, who has been in power since 1969. The conflict has turned into a civil war, and Gadhafi's forces are accused of orchestrating deadly attacks on civilians.
The rebels have taken over much of the eastern half of Libya. They also control pockets in the west, including the vital port city of Misrata, about 125 miles (200 kilometers) from the capital.
A coalition including France, Britain and the United States began striking Gadhafi's forces under a United Nations resolution to protect civilians on March 19. NATO assumed control of the air campaign over Libya on March 31 and is joined by a number of Arab allies.
In Benghazi, Ghoga, the spokesman for the rebels' National Transitional Council, said 38 of Gadhafi's military officers _ six of them high-ranking _ defected to the rebel side and fled to Tunisia Friday.
"This will lead to the further isolation of the Gadhafi regime," he said.
Ghoga said the rebels have been informed that Gadhafi is in contact with leaders in South Africa and France in an attempt to find a possible home in exile. Such claims have been filtering out for weeks, but there is no evidence that the Libyan leader is seeking a way out.
On Saturday, a spokesman for the rebels' western mountain military council confirmed that rebels are coordinating with individual cells and with an underground rebel guerrilla group known as the Tripoli Council. The main goals are to cut the fuel from Gadhafi forces, Gomaa Ibrahim said.
Meanwhile, a spokesman for the Tripoli Council said that their fighters have been carrying out selective attacks on Gadhafi forces in the capital.
The spokesman, who requested anonymity for fear of reprisals, said that the rebels are coordinating for "the zero hour, when rebels from liberated cities enter Tripoli."
"It will be a tremendous mission. The city is now besieged by 13 different security brigades, well armed and well equipped. Gadhafi has always said that his loyalists will sabotage the city if he falls. So this will be our mission: to mob it and clean it of mercenaries."
In Benghazi, Ghoga said there are constant contacts between rebels in different parts of the country, but he did not elaborate.
The rebels got a boost Saturday from several players from Libya's national soccer team who announced their support for the fight to end Gadhafi's rule.
Seventeen players from the team defected while they were in the West African nation of Mali for a match and later traveled to Tunisia, Ghoga said.
The players crossed into rebel-held territory in Libya's western mountains, and visited with residents in the town of Zintan on Saturday, said Gomaa Ibrahim, a spokesman for rebel fighters in that area.
Four of the players are from Tripoli's most popular team, al-Ahly, where one of Gadhafi's sons, al-Saadi, once played, said Ghoga. Al-Saadi now heads Libya's Football Federation.
In a video posted Saturday on a rebel Facebook page under the title "the national team announces its defection," one man said: "God willing, Tripoli will be liberated by this mountain. This is a message to the agents to abandon their weapons because Libya will be free, sooner or later."
Associated Press writers Maggie Michael in Cairo, Rami al-Shaheibi in Benghazi, Libya, and Slobodan Lekic in Brussels contributed to this report.