British and French attack helicopters struck for the first time inside Libya, giving the NATO campaign more muscle against Moammar Gadhafi's forces. Hours later, Tripoli was hit by another round of airstrikes and at least eight explosions sounded in the capital.
The use of helicopters significantly ramped up NATO's operations and was a major boost to Libyan rebels, just a day after the fighters forced government troops from three western towns and broke the siege of a fourth. It was yet another erosion of Gadhafi's power since the eruption in mid-February of the uprising to end his 42-year rule.
NATO said the helicopters struck troops trying to hide in populated areas, military vehicles and equipment. Lt. Gen. Charles Bouchard, commander of the Libya operation, said the engagement "demonstrates the unique capabilities brought to bear by attack helicopters."
Until now, NATO has relied on attack jets, generally flying above 15,000 feet (4,500 meters) _ nearly three miles (five kilometers) high. The jets primarily strike government targets but there have been cases where they missed and hit rebels instead.
The helicopters give the alliance a key advantage in close-up combat, flying at much lower altitudes.
The British Apaches hit two targets near the eastern oil town of Brega, according British Maj. Gen. Nick Pope, and separate Royal Air Force aircraft destroyed another military installation near Brega and two ammunition bunkers at the large Waddan depot in central Libya.
Brega is of strategic importance to Libya's oil industry and lies on the coastal road along the Mediterranean that leads to the capital, Tripoli. In the early days of the uprising against Gadhafi, it went back and forth between rebel and loyalist hands, but later the front line settled to the east of the town, leaving Brega under Gadhafi's control.
The French Gazelle and Tiger helicopters struck 15 military vehicles and five military command buildings, said Col. Thierry Burkhard. All the helicopters returned safely, the French and British said.
British Defense Secretary Liam Fox said the "use of the attack helicopters is a logical extension" in NATO's campaign and indicated more would be used in the future.
"We will continue with the methods we have to degrade his (Gadhafi's) command and control, to degrade his supplies," Fox said from Singapore, where he was attending an Asian security conference.
The head of the rebels' Transitional National Council, Mustafa Abdul-Jalil, welcomed the helicopter attacks and emphasized that they launched from ships outside Libya.
"We welcome any measures to expedite the departure of Moammar Gadhafi, but at the same time we maintain the sovereignty of the Libyan state," Abdul-Jalil told reporters Saturday.
The conflict in Libya appears at a stalemate after nearly four months. NATO airstrikes have kept the outgunned rebels from being overrun, but the rebels have been unable to mount an effective offensive against Gadhafi's better equipped forces.
Gadhafi's regime has been slowly crumbling from within. A significant number of officers and several Cabinet ministers have defected, and most have expressed support for the opposition, but Gadhafi's hold on power shows little sign of loosening.
Gadhafi has been seen in public rarely and heard even less frequently since a NATO airstrike on his compound killed one of his sons on April 30. Questions are arising about the physical and mental state of the 69-year-old dictator, who has ruled Libya since 1969.
The NATO strikes on Saturday targeted an educational institute in eastern Tripoli where military officials and civilians studied engineering, computers and communications, according to an official who requested anonymity in line with government policy.
Libyan rebels on Friday won control of four towns in the western Nafusa mountain range, where government forces have besieged and periodically shelled rebel-held areas.
The small rebel force in the western mountains is unlikely to threaten Gadhafi's hold on Tripoli, 45 miles (70 kilometers) northwest, but the victories could bring relief to local residents by opening up roads between their communities. The western mountain population is tiny compared with the large rebel-held territories in east Libya.
Fighting continued Saturday in another part of the mountain range, near the border with Tunisia. A resident of the town of Nalut, Mohammed Jernaz, said via Skype that Gadhafi's forces fired grad rockets, injuring 10 people.
A video posted by Nalut activists on YouTube showed injured men covered with blood being transported in the back of pickup trucks. The video's authenticity could not be confirmed.
Abdul-Jalil, the head of the rebel council, and other leaders met with British Foreign Secretary William Hague in the rebels' de facto capital, Benghazi.
Hague is one of the highest-ranking foreign officials to visit rebel-held territory in eastern Libya.
He traveled with another British Cabinet minister, International Development Secretary Andrew Mitchell, on a visit Hague said was to show support for those fighting Gadhafi's rule.
Hague called the National Transitional Council "the legitimate representation of the Libyan people," but fell short of calling it a government as other NATO countries like France and Italy have.
He said that British efforts to support rebel fighters were in full swing, and included providing radios, uniforms and bulletproof vests.
"I believe now the momentum has shifted increasingly against the Gadhafi regime," said Hague.
Associated Press writers Diaa Hadid in Tripoli, Alex Kennedy in Singapore, David Stringer in London, Jamey Keaten in Paris and Don Melvin in Brussels contributed to this report.