Tripoli, Libya (CNN) -- Libyan government forces fired a missile at an Italian warship in the Mediterranean Sea on Wednesday in a rare attack on the NATO fleet offshore, a government spokesman said.

The frigate Bersagliere was about 19 kilometers (12 miles) off the Libyan city of Zlitan when the missile fell harmlessly into the sea about 2 km away, the Italian defense ministry and NATO reported.

"The ship was not harmed and continued on its mission," NATO said in a statement. "NATO ships go in harm's way to seek those military targets which continue to threaten the people of Libya."

In Tripoli, government spokesman Musa Ibrahim told reporters that the missile had been launched by troops that remain loyal to longtime Libyan leader Moammar Gadhafi.

"We have amazing capabilities that we have not felt that we need to use," Ibrahim said. "Our army is still very strong. We

haven't used our real military power."

He discounted allied claims that pro-Gadhafi forces had been reduced to 20% of their capabilities, adding, "For God's sake, if we are down here to 20%, what am I doing here?"

Gadhafi's forces have been battling a nearly six-month-long revolt that has split Libya roughly in half. NATO planes and warships joined the fight in March, pounding government troops under a U.N. mandate to protect civilians from reprisals by Gadhafi loyalists.

Though most of the allied campaign has been conducted from the air, NATO warships reported fighting at least two brief sea engagements with pro-Gadhafi forces off the port city of Misrata in May.

CNN's Ivan Watson in Tripoli and Livia Borghese in Rome contributed to this report.