Libyan rebels painted the roofs of their vehicles bright pink on Friday to avoid more friendly fire casualties after a NATO airstrike they said killed five fighters.
"We are painting the trucks so NATO won't hit us," said Salam Salim, a 29-year-old rebel militiaman.
The strike Thursday hit a rebel tank column as it advanced on the disputed oil port of Brega, causing a confused insurgent retreat back from Ajdabiya, gateway to the uprising's stronghold in Benghazi.
NATO, which is enforcing a no-fly zone in Libya aimed at protecting civilians, on Friday acknowledged that its planes were probably responsible for the friendly fire incident, the second in a week. Officials noted that the alliance had no information that the rebels were now using tanks that once belonged to Moammar Gadhafi's military.
Rebels were still angry and jittery on Friday about the accident and scattered quickly when a volley of artillery shells from Gadhafi forces thumped around the western gate to Ajdabiya in the afternoon.
Ahmed Ignashy, a doctor at Ajdabiya hospital, said about six rebels were wounded in skirmishes Friday 12 miles west along the Mediterranean coast road.
He expressed the despondency in rebel ranks and impatience that NATO airpower has not been decisive. "I don't know what is happening, really. NATO struck us yesterday and today tanks from the Gadhafi forces. Where is NATO?"
Another NATO strike last week killed 13 rebels, including ambulance staff, on the outskirts of Brega.
"Twice they've hit us by accident now," grumbled Belgassim Awamy, a rebel volunteer near the western entrance of Ajdabiya.
"NATO is an alliance against the Libyan people," said Alaa Senudry, another rebel standing nearby.
NATO says Gadhafi forces are sheltering near civilian areas, making it difficult to hit them effectively from the air.
Some rebels insisted Gadhafi aircraft had staged Thursday's attack, despite the fact that his air force has been grounded by the NATO planes.
"That was Moammar, it came from the south," said Wanis Boumarie, a former policeman turned rebel volunteer, when another rebel blamed the attack on NATO.
In other developments Friday:
- Heavy shelling was heard at nightfall outside Misrata, the only major rebel-held city in western Libya, where some neighborhoods have been nearly abandoned after residents fled to safer areas during weeks of fighting. Nearly all buildings were pockmarked from gunfire. NATO has been cautious about waging bombing runs in Misrata because the fighting in mostly within civilian areas.
- In the rebel stronghold of Benghazi in eastern Libya angry crowds fired into the air and chanted against Gadhafi's regime as militiamen killed in an accidental NATO airstrike were carried for burial. "The martyrs' blood is not shed in vain!" cried some of the thousands of people gathered in central Benghazi to pray and mourn some of the dead from the attack on rebel tanks and vehicles.
- Microsoft Corp. was working to free its manager in charge Libyan operations who has been held since March 19. Microsoft said it had no information about the reasons for Khalid Elhasumi's detention. (Microsoft is a partner in the joint venture that operates msnbc.com.)