Muammar Gaddafi supporters rocketed a front line south of Tripoli today, testing the patience of the country's new leaders as a grace period for the holdouts to surrender runs out.

Also today, Interpol said it has issued its top most-wanted alert for the arrest of Gaddafi, his son Seif al-Islam and the country's ex-head of military intelligence, all sought by the International Criminal Court for alleged crimes against humanity.

Gaddafi hasn't been seen in public for months and went underground after anti-regime fighters swept into Tripoli on August 21.

As the National Transitional Council tries to establish its authority in Libya, speculation about Gaddafi's whereabouts has centred on his Mediterranean hometown of Sirte, southern Sabha, and Bani Walid, 90 miles south-east of Tripoli.

Gaddafi loyalists in all three towns have been given until Saturday to surrender, or face an all-out battle.

Gaddafi holdouts fired mortars and rockets from Bani Walid. National Transitional Council forces around Bani Walid unloaded hundreds of boxes of ammunition and ordinance and reinforcements in gun-mounted trucks rushed toward the front line in the desert sand.

"Today marks the last day of the deadline," said Abdel-Razak al-Nazouri, a commander in the region. "Our men are preparing for an attack, probably tomorrow."

Another transitional council fighter in the region, Osama al-Fassi, said: "We are preparing for war."

The transitional council fighters said they had captured 10 Gaddafi fighters they suspected were spying on them. Dressed in fatigues, their hands tied behind their backs, the 10 were being held in two pickup trucks at the Wishtat checkpoint, about 20 mile from Bani Walid. An Associated Press photographer who saw the truck said two of the 10 appeared to be dead.

At one point, an ambulance rushed into Wishtat and a transitional council fighter on a stretcher was picked up and taken to a field hospital. Officials refused to say how he had been injured.

The seizure of the capital by the then-rebel forces last month effectively ended nearly 42 years of Gaddafi's autocratic, violent and unpredictable rule. The new leaders now control most of the country, but as long as Gaddafi is on the loose, able to urge his followers on with messages from underground, they cannot claim total victory.

In Tripoli yesterday, Mahmoud Jibril, the head of the former rebels' acting Cabinet, said that a new government can be formed only after the whole country is "liberated."

He also told reporters negotiations for the peaceful takeover of Bani Walid, Sirte and Sabha were an opportunity to avoid further bloodshed, but said his forces would respond if attacked. He criticised Bani Walid's leaders, saying they had shown "no real initiatives or intentions to give peace a chance and bring unity back to the Libya people."

Some say prominent regime loyalists, including Gaddafi's son and one-time heir apparent, Seif al-Islam, could be in Bani Walid.

Mahmoud Shammam, a spokesman for the new leadership, said Gaddafi's inner circle has been broken up, with most of its members under arrest or in the process of handing themselves over.

Gaddafi, Seif al-Islam and the country's ex-head of military intelligence, Abdullah al-Senoussi, are the only people at large who matter, Mr Shammam said.

Interpol Secretary General Ronald Noble called the red notices it issued to its 188 member countries today "a powerful tool" in helping lead to the capture of the Gaddafis and al-Senoussi. A red notice is the equivalent to being on the Lyon, France-based international police body's most-wanted list.

Gen Noble said the notices will "significantly restrict the ability of all three men to cross international borders."

Yesterday, in an audio message broadcast on a Syrian-based TV station, a man believed to be Gaddafi dismissed talk of his flight.