The attack was carried out on Thursday near the oil town of Brega.
“It was a NATO air strike on us. We were near our vehicles near Brega,” Reuters quoted a wounded fighter as saying from his stretcher at the Ajdabiyah hospital.
The attack marks the second deadly NATO strike on Libyan revolutionary forces in less than a week. Thirteen also died in another West-led air strike near Brega on Saturday.
“We were standing by our tanks and NATO fired two rockets at us,” one anti-Gaddafi fighter said, describing NATO officials as liars. “They are siding with Gaddafi.”
Libyan anti-government forces, inspired by revolutions that toppled authoritarian rulers in neighboring Tunisia and Egypt, are fighting to dethrone Gaddafi after suffering under his despotic rule for over 41 years.
The violent repression of anti-government protesters by Gaddafi loyalists has claimed the lives of thousands of people since the beginning of the revolution in mid-February.
Dozens of civilians have also been killed in crisis-hit Libya since US-led forces launched aerial and sea attacks on the North African country began on the heels of a United Nations resolution in last month.
UN Security Council Resolution 1973 calls for an immediate ceasefire and a no-fly zone, authorizing “all necessary measures” to protect Libyan civilians except for a ground incursion.