NATO announced Saturday it had for the first time used attack helicopters in Libya, striking military vehicles, military equipment and forces backing embattled leader Colonel Muammar al-Qaddafi.

"Attack helicopters under NATO command were used for the first time on 4 June, 2011 in military operations over Libya as part of Operation Unified Protector," the Atlantic Alliance said in a statement.

"The targets struck included military vehicles, military equipment and fielded forces" of the Qaddafi regime, said the statement, without detailing exactly where the strikes had taken place.

The Apaches hit two targets near the coastal city of Brega, according to a statement from the Ministry of Defense in London.

It said they took off from HMS Ocean, stationed off the Libyan coast and returned safely after completing their mission in the early morning hours.

The French helicopters took off from the helicopter transport ship Tonnerre in the Mediterranean, said Col. Thierry Burkhard. He said the French helicopters struck 15 military vehicles and 5 military command buildings, without identifying the sites or their location.

He said the French helicopters came under light firearms fire but were not hit or damaged. Burkhard said the operation was aimed at putting "additional pressure on the Gadhafi forces who continue to threaten the civilian population."

Until now, NATO has relied on attack jets, generally flying above 15,000 feet (4,500 meters) -- nearly three miles (five kilometers) high and pounding Gadhafi targets in relentless overnight bombings.

But the helicopters are a game-changer, giving the alliance a key advantage in close-up combat, flying at much lower altitudes.

The news came as a report in Japan said that authorities there had frozen $4.4 billion in assets belonging to Qaddafi and his entourage under the terms of a UN Security Council resolution.

The assets included bank savings, the Yomiuri Shimbun newspaper reported citing data of the finance ministry, without giving fuller details. A spokesperson was not immediately available to comment on the report.

The UN Security Council, with strong support from Arab and African nations, on February 26 unanimously passed sanctions against the Qaddafiregime with the aim of stopping a crackdown on anti-government forces.

Meanwhile in London the Ministry of Defense confirmed British Apache helicopters took part in the Saturday's helicopter attacks. "Yes, we confirm" their intervention, a spokeswoman said, without giving further details.

London, which has since March 19 taken part in the international coalition's operations in Libya, announced late last month it was sending in four attack helicopters to be based on HMS Ocean off the north African coast.

Lieutenant General Charles Bouchard, commander in chief of the NATO mission in Libya, said "this success demonstrates the unique possibilities offered" by using combat helicopters.

"The use of attack helicopters provides the NATO operation with additional flexibility to track and engage pro-Qaddafi forces who deliberately target civilians and attempt to hide in populated areas," the statement went on.

It quoted Bouchard, the Canadian officer in charge of Operation Unified Protector, as saying: "We will continue to use these means when and where necessary, with the same precision as in all our missions."

NATO forces "are constantly reviewing their operations and use of available assets, including attack helicopters, to best maintain the momentum and increase the pressure on pro-Qaddafi forces."

The statement recalled that NATO's operation was being conducted under UN Security Resolution 1973, which did not authorize the sending of troops to occupy Libya but "which calls for an immediate end to all attacks against civilians and authorized all necessary measures to protect civilians and civilian populated areas under threat of attack in Libya."

At the end of May, Bouchard said French and British attack helicopters would allow NATO to conduct an "effective and aggressive" mission against Qaddafi forces threatening the civilian population.

"It's an additional capability to pinpoint these vehicles that are much more difficult to see from aircraft at high altitude," he said from his headquarters in Naples, Italy.

France was contributing four Tigre attack helicopters while Britain offered four Apaches, NATO military officials said, adding that the helicopters were being prepared to fly over sea water and desert conditions.

The choppers were based respectively on the helicopter carriers Tonnerre and HMS Ocean. The Tonnerre was also transporting a dozen Gazelle helicopters that are older than the Tigres, an alliance military official said.

Insisting that NATO had no intention to put troops on the ground, Bouchard said in late May: "The helicopters that are being provided to us are armed and attack helicopters and they are not the type that do mass movements of troops on the ground."

The Associated Press contributed to this report