The claim came as fierce fighting continued on the ground on Wednesday as forces loyal to embattled Libyan leader Muammar Gaddafi continued their offensive against anti-government rebels across the north African state.
Addressing journalists at an air base in southern Italy, from which Royal Air Force (RAF) warplanes have been operating, Air Vice Marshall Greg Bagwell said international coalition forces could operate with impunity over Libya.
"Effectively, [Libya's] air force no longer exists as a fighting force," said Bagwell. "And his [Libyan leader Muammar Gaddafi's] integrated air defence system and command and control networks are severely degraded to the point that we can operate over his airspace with impunity," he said.
Bagwell said US, French and British forces involved in the strikes that began on Saturday had "taken away (Gaddafi's) eyes and ears" and "destroyed the majority of his air force".
Bagwell said coalition forces were also targeting Gaddafi's ground forces.
"We have the Libyan ground forces under constant observation and we attack them whenever they threaten or attack civilians or population centres," he said.
The US military confirmed this on Wednesday, saying ground troops loyal to Gaddafi who are threatening rebel-held cities are now being targeted by coalition airstrikes.
"We are putting pressure on Gaddafi's ground forces that are threatening cities," Rear Admiral Gerard Hueber, US chief of staff for the Libya mission, said.
He also said that the coalition no-fly zone now stretches across all of coastal Libya.
Hueber said that Gaddafi's military remains in violation of a UN Security Council resolution calling for an end to attacks on civilians, with fighting reported in several cities.
Enforcement of the no-fly zone has so far been carried out primarily by French, American and British forces but confusion over the command structure for the operation continued on Wednesday as NATO member states failed to agree on a role for the military alliance after a third day of talks.
Fierce fighting continues
Undaunted by air strikes launched by coalition warplanes aimed at enforcing a no-fly zone, pro-Gaddafi forces pressed ahead with their assaults on the towns of Misurata, Ajdabiya and Zintan in the past 24 hours.
Pro-democracy fighters ranged against Gaddafi are finding the going tough.
"On the ground, the situation in [city of] Ajdabiya is that there have been some air strikes there by western powers, but they haven't managed to dislodge Gaddafi's tanks," Al Jazeera's James Bays, reporting from the eastern city of Benghazi, said.Mostly outgunned and with little command structure, they have been left to run sporadic raids against Gaddafi's troops, before falling back to their original lines.
"In [the town of] Misurata at least 23 people have been killed in recent hours. The opposition is asking for international medical help. They are asking for a medical ship to come to the port, they say Gaddafi controls the hospital there."
Reuters news agency quoted a doctor there saying government tanks were closing in on the hospital and shelling the area.
Meanwhile, as night fell in the Libyan capital of Tripoli on Wednesday, locals said they heard eight explosions in the east of the city and saw smoke rising into the night sky, Reuters reported.
Amid raging fighting, Gaddafi insisted he was "ready for battle, be it long or short".
"We will win this battle," he said in an address during a public appearance at his Bab Al-Aziziyah compound in Tripoli that was the target on Sunday of a coalition missile strike, Libyan state television reported.
He also railed against the coalition forces, saying: "This assault ... is by a bunch of fascists who will end up in the dustbin of history."
Opposition forms 'interim government'
Meanwhile, also on Wednesday, Libya's pro-democracy fighters formed an "interim government", headed by Mahmoud Jibril, who had been working as a representative to foreign powers.
He is best known on the international stage for meeting Nicolas Sarkozy, the French president, which led to France diplomatically recognising the rebels' transitional council as the sole representative of the Libyan people.
Opposition spokesman Nisan Gouriani told Al Jazeera: "The provisional national council is a legislative body, but we need an executive body to take control and provide an administration."
He said the rebels' "position has been very clear from the beginning - that Libya is one unit".
"Our capital is Tripoli and will forever be Tripoli," he said. "We are striving to liberate the western parts of the country, and Tripoli, and keep the country united. We would like to emphasise this over and over again."
The rebels had been wary of calling their nascent administration in their Benghazi stronghold an interim government seemingly cautious of signifying a split in the country.
"But they remain committed to one Libya," our correspondent said. "They want the people of Libya to remain united, just without Gaddafi."