Rebels were seen fleeing after they say several of their tanks were destroyed by airstrikes. A NATO official in Brussels says the alliance will look into the claims, but had no other information.
In a separate statement, NATO dismissed Libyan claims that British warplanes struck the country's largest oil field, saying the attacks were carried out by government forces.
At least two rebels were killed and more than a dozen injured, a doctor said.
The attack would be the second accidental NATO strike against rebel forces in less than a week.
Meantime, Secretary of State Hillary Clinton says Libyan leader Moammar Gadhafi must leave the country in order for NATO to stop bombing Libya.
"Mister Gadhafi knows what he must do. There needs to be a ceasefire. His forces need to withdraw from the cities that they have forcibly taken at great violence and human cost. There needs to be a decision made about his departure from power, and as the foreign minister said, his departure from Libya," she said.
A senior White House official said Gadhafi sent a letter to President Barack Obama on Wednesday asking him to stop the bombing, but that official says the White House is not taking that letter seriously.
The Associated Press contributed to this report.