By Michael Georgy and Maria Golovnina
TRIPOLI (Reuters) - Libyan rebels repelled a counter-offensive by leader Muammar Gaddafi's troop on Friday, but appealed to foreign powers to impose a no-fly zone to stop further attacks overrunning their three-week uprising.
Government forces, with air supremacy and a big advantage in tanks, still appear to have regained the momentum and their push could overtake sluggish international efforts to halt Gaddafi.
The sound of explosions and small arms fire came from Ras Lanuf on Friday as government troops landed from the sea backed by tanks and air power fought to recapture the oil port town.
After hours of fighting, insurgents withdrew east of the small town and a large column of black smoke billowed from storage tanks at ras Lanuf's oil installation. Rebels said the plant was hit by a series of government air strikes, but the Libyan government denied bombing the storage tanks.
The insurgents then regrouped outside the town and counter-attacked and seized it back, they said.
"There has been intense fighting with Gaddafi's forces. They have withdrawn from the residential area to the west. We are now combing the area," rebel fighter Mohammed Aboul Hassan told Reuters by telephone from Ras Lanuf.
"TIME FOR ACTION"
As a host of international bodies agonies over whether, or how to impose a no-fly zone, Gaddafi's warplanes are carrying out air strikes seemingly unhindered by insurgent anti-aircraft guns mounted on the back of pick-up trucks.
Many rebels were angry at international inaction.
"Where is the West? How are they helping? What are they doing," shouted one angry fighter.
Gaddafi's son Saif al-Islam told the rebels they faced a full-scale assault to crush their uprising which began after Hosni Mubarak was overthrown in neighboring Egypt a month ago.
"It's time for action. We are moving now," he told Reuters in an interview on Thursday.
In Tripoli, Libyan security forces used tear gas and fired in the air to disperse worshippers near a mosque before they could even attempt any protest, a Libyan said, citing witnesses.
West of the capital, the revolt in Zawiyah was crushed and state television broadcast live pictures of jubilant Gaddafi supporters waving green flags in the main square.
The only town now holding out in western Libya is Misrata, about 200 km (125 miles) east of Tripoli. It was calm on Friday, but rebels said they were expecting an attack to come soon.
As EU heads of government prepared to meet in Brussels on Friday, Libya's insurgent leader warned that any delay in imposing a no-fly zone could let Gaddafi regain control.
"We ask the international community to shoulder their responsibilities," Mustafa Abdel-Jalil, head of the National Libyan Council, told the BBC.
"The Libyans are being cleansed by Gaddafi's air force. We asked for a no-fly zone to be imposed from day one, we also want a sea embargo," he said.
Some 15,000 worshippers gathered outside the courthouse that has become the headquarters of the National Libyan Council in the rebel stronghold of Benghazi.
"Help us to become a democratic country," said one banner strung between lampposts and written in English and Arabic.
But Britain and France faced skepticism from other EU members as they pushed for tough action against Gaddafi, with Germany sounding a note of caution.
French President Nicolas Sarkozy wants the EU to follow his lead and recognized the Libyan National Council as the legitimate authority.
He said France and Britain were "open," if the United Nations backed it, to "defensive" air strikes against Gaddafi's forces if they used chemical weapons or warplanes to target the civilian population.
But in practice, any military action will require the participation of the United States which, along with NATO, has expressed doubt over the wisdom of imposing no-fly zones without full international backing and a legal justification.
U.S. National Intelligence chief James Clapper said Gaddafi was "in this for the long haul" and was likely to prevail.
(Additional reporting by Mohammed Abbas in Brega, Tom Pfeiffer in Benghazi, Luke Baker, David Brunnstrom, Missy Ryan and Lucien Toyer in Brussels, Paul Eckert and Tabassum Zakaria in Washington, Stefano Ambrogi and Olesya Dmitracova in London, John Irish in Paris, Stephanie Nebehay in Geneva, Harry Papachristou in Athens; Writing by Andrew Dobbie and Jon Hemming; Editing by Giles Elgood)