By Maria Golovnina and Patrick Worsnip
TRIPOLI/UNITED NATIONS (Reuters) - Muammar Gaddafi warned the rebel stronghold of Benghazi he would storm the city in the night showing no mercy, while the United Nations moved toward a resolution allowing air strikes to stop him.
"We will come zenga, zenga. House by house, room by room," he said in a radio address to the eastern city.
Thousands of residents of Benghazi gathered in a central square, waving anti-Gaddafi tricolour flags and chanting defiance of the man who has ruled the country for four decades.
"It's over. The issue has been decided," Gaddafi said, offering pardon to those who lay down their arms. "We are coming tonight...We will have no mercy and no pity with them."
Gaddafi's troops, far better armed than the rebels, appeared to be still at least 100 km (60 miles) from Benghazi and it was unclear if his threat to seize and purge the city in the night was anything more than bluster. But Thursday saw three air raids on the city, residents and a rebel spokesman said.
The threats, at the very least, raise the sense that a decisive moment had come in an month-old uprising inspired by rebellions against autocratic rule elsewhere in the Arab world.
The United Nations Security Council was preparing to vote on Thursday night on a resolution, backed by Western and Arab powers, that could open the way for air strikes to protect civilians from retribution by the man who has ruled Libya for four decades.
The draft, obtained by Reuters, submitted by France, Britain and Lebanon, would authorize a no-fly zone and 'all necessary measures' to protect civilians under threat.
It ruled out any "occupation force"; a nod both to Arab sensitivities and to Western capitals such as London and Washington already chastened by involvement in wars in Afghanistan and Iraq.
"We are very concerned about the situation in Libya and the violence that is being perpetrated by the Gaddafi regime against its people," White House spokesman Jay Carney said.
"We are acting with a great sense of urgency together with our international partners to take the kinds of actions that we believe will protect Libyan citizens and move toward a situation where Gaddafi is no longer in power," he said.
Paris believes there is enough support to pass the resolution, scheduled for 2200 GMT. Military intervention could follow within hours, a senior French diplomatic source said.
Gaddafi's Defense Ministry warned of swift retaliation if the United Nations Security Council, meeting in emergency session Thursday evening, triggered military action proposed by Arab states and Western powers.
"Any foreign military act against Libya will expose all air and maritime traffic in the Mediterranean Sea to danger and civilian and military (facilities) will become targets of Libya's counter-attack," the ministry said in a statement.
Any action could include France, Britain, possibly the United States, the source said. Diplomats told Reuters between two and five Arab countries may join the military action.
TIDE IN MIDDLE EAST
Gaddafi, famously labeled the 'mad dog of the Middle East' by U.S. president Ronald Reagan in 1986, has described the rebels as dogs, rats and foreign agents.
International diplomacy has moved slowly as Gaddafi's troops have cracked down hard on an uprising inspired by the overthrow of authoritarian leaders in Tunis and Cairo as well as mass protests in Bahrain.
Libyan state television said government troops had taken Zueitina, an oil port on the coastal highway 130 km (80 miles) from Benghazi, but the rebels said they had surrounded the pro-Gaddafi units on the approaches to the town.
Residential areas of Ajdabiyah, a strategic town on the coast road to Benghazi, was the scene of heavy fighting on Thursday and around 30 people were killed, Al Arabiya reported.
On the approaches to Ajdabiyah, burned-out cars lay by the roadside while Libyan government forces showed the foreign media artillery, tanks and mobile rocket launchers -- much heavier weapons than those used by the rebels.
In Libya's third city, Misrata, about 200 km (130 miles) east of Tripoli, rebels and residents said they were preparing for a new attack by Libyan troops, who had shelled the coastal city overnight. A government spokesman said Gaddafi's forces expected to be in control of Misrata by Friday morning.
Russia, China, Germany, India and other council members have voiced doubts about the proposal for a no-fly zone, but comment from Paris suggest they might abstain rather than vote against. Italy, a potential base for military action, ruled out military intervention in the oil-exporting country.
U.S. Secretary of State Hillary Clinton laid out the case for removing Gaddafi in a televised question and answer program with Tunisians.
"Tunisia knows very well that if Gaddafi does not go, he will most likely cause trouble for you, for Egypt and for everybody else. That is just his nature. You know, there are some creatures that are like that," she said.
(Additional reporting by a Reuters reporter in Benghazi, Michael Georgy in Tripoli, Mariam Karouny and Tarek Amara in Tunisia, Louis Charbonneau and Patrick Worsnip at the United Nations; Writing by Ralph Boulton; Editing by Louise Ireland)