Attack helicopters have struck Moamer Kadhafi's forces, NATO said Saturday as China acknowledged contact with rebels fighting to oust the Libyan leader and Russia prepared to send an envoy to broker a truce.
As the NATO-led war entered a new phase, explosions rattled Tripoli overnight and US lawmakers chided President Barack Obama for failing to obtain congressional approval for military action in Libya.
"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 military alliance said in a statement.
"The targets struck included military vehicles, military equipment and fielded forces" of the Kadhafi regime, said the statement, without detailing exactly where the strikes had taken place.
NATO said it deployed British Apache choppers and French Tigres in the attacks launched as part of the aerial campaign to protect Libyan civilians from Kadhafi's forces in line with a UN resolution that barred ground troops.
"The use of attack helicopters provides the NATO operation with additional flexibility to track and engage pro-Kadhafi forces who deliberately target civilians and attempt to hide in populated areas," said a NATO statement.
On the diplomatic front, China acknowledged for the first time contact with Libya's rebels as Russia prepared to send an envoy to help mediate a settlement to the conflict.
China, a veto-wielding member of the UN Security Council, said its ambassador to Qatar, Zhang Zhiliang, held talks with Mustafa Abdul Jalil of the Libyan rebel National Transitional Council in recent days to discuss the conflict in the oil-rich nation.
"The two sides exchanged views on the Libyan situation," Beijing's foreign ministry spokesman, Hong Lei, said without elaborating on the time and place of the meeting.
"China's position on the Libyan issue is clear -- we hope that the Libyan crisis can be resolved through political means and that the future of Libya is decided by the Libyan people."
Russian President Dmitry Medvedev said Moscow would send an envoy to Tripoli and the rebels' capital of Benghazi to mediate, the Italian news agency ANSA reported, quoting diplomats.
"We would like as much as possible for the problem to be resolved through negotiations and not by military means," Medvedev said.
Since February, Kadhafi's forces have been embroiled in a battle with rebels looking to put an end to his more than four decades in power.
The US House of Representatives, meanwhile, approved a vote that rebuked President Obama for maintaining a role in the NATO mission while ignoring Congress, but stopped short of calling for an end to the mission.
The measure calls for a report from the White House within 14 days explaining US objectives in Libya, associated costs, the expected duration of US involvement and an explanation about why Obama didn't seek congressional permission.
It warned Congress "has the constitutional prerogative to withhold funding for any unauthorized use" of the US military.
Another bill seeking a withdrawal of US forces involved in the NATO mission within 15 days of passage failed 265-148, with 87 Republicans voting in favor.
Separately, Washington accused Qatar of violating humanitarian norms by deporting to Benghazi Iman al-Obeidi, a Libyan woman who charged she had been raped by Kadhafi's soldiers.
US officials had repeatedly asked Qatar's government to allow "travel with UNHCR (High Commissioner for Refugees) officials to a safe third country," State Department deputy spokesman Mark Toner said.
"So we were disappointed at her forced return (to Libya), and we believe it's a breach of humanitarian norms."
In Geneva, the UNHCR also slammed Qatar's decision to send Obeidi back to Libya, saying it "violates international law."
Obeidi attracted international media attention when she stormed into Tripoli's Rixos hotel on March 26, threw open her coat to reveal scars and bruises on her body to expose her ordeal.
But as she screamed: "Film me, film me, show the whole world all they did to me," she was dragged off by security guards amid scenes of mayhem as journalists were shoved aside while trying to intervene.
A Libyan rebel official told AFP last month that Obeidi had escaped from Libya to Qatar with the help of rebels.
Off the Tunisian coast, up to 270 migrants were missing after a ship packed with refugees fleeing Libya and headed for Italy capsized, Tunisian authorities said.
Army and coastguard teams lifted 570 people off the overcrowded vessel after it ran aground and capsized near Tunisia's Kerkennah islands on Wednesday.
But between 200 and 270 were still missing after they tried to scramble aboard a flotilla of rescue boats, Tunisia's official TAP news agency said.
The Tunisian coastguard said it had recovered two bodies, dismissing claims by the Red Crescent that 123 bodies had been fished from the sea.