By Michael Georgy and Maria Golovnina
TRIPOLI (Reuters) - Troops loyal to Libyan leader Muammar Gaddafi intensified their counter-offensive on Friday to retake ground from out-gunned insurgents who appealed to foreign powers to impose a no-fly zone to stop the onslaught.
Government forces, with air supremacy and a big advantage in tanks, appear to have regained the momentum in the three-week old conflict and if their push proceeds apace it 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.
A large column of black smoke billowed from storage tanks at an oil installation, television pictures showed, after what Arab channels said was a series of government air strikes.
Insurgents withdrew their last main checkpoint in Ras Lanuf on Friday, setting it up 15-20 km (10-13 miles) to the east, but then counter-attacked and said Gaddafi's forces had withdrawn from the residential area of Ras Lanuf.
"War is always backwards and forwards. God willing, we go forwards again," said rebel Jomaa Irjai, 22, clutching his AK-47 Kalashnikov rifle close to the frontline.
"TIME FOR ACTION"
As a host of international bodies agonize over whether, or how to impose a no-fly zone, Gaddafi's warplanes are carrying out air strikes 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 appeared all but crushed, with rebels clinging to only parts of the shattered city. Residents described scenes of carnage, with women and children among the dead, but there was no fighting on Friday.
"This is the calm before the storm," a fighter named Ibrahim told Reuters by telephone.
"All we want is a no-fly zone. To ban him (Gaddafi) from flying his planes. I swear to God, if this happens we will be talking to you from Bab al-Aziziyah in a week," he said, referring to Gaddafi's compound in the Libyan capital.
The only other rebel holdout in western Libya, Misrata about 200 km (125 miles) east of Tripoli, was also calm for now, 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)