TRIPOLI, Libya - Revolutionary fighters in Libya are planning a new assault on a loyalist stronghold southeast of Tripoli where forces loyal to Moammar Gadhafi have put up fierce resistance for two weeks, a commander said Friday.

Attempts to take the desert city of Bani Walid have failed, as loyalist forces massed inside direct punishing mortar, rocket and machine-gun fire at fighters crowded around the northern gate. A brigade of fighters will try instead to attack the city from the southeastern side, said field commander Abdel-Salam Genouna.

The fierce fighting for Bani Walid demonstrates the difficulty Libya's new rulers have had in trying to consolidate their control over the entire country a month after their forces swept into the capital, Tripoli, and drove Gadhafi into hiding.

The country's new leaders in the National Transitional Council insist the holdouts in Bani Walid, Gadhafi's hometown of Sirte and Sabha, deep in the southern desert, are die-hard supporters -- some of whom fled Tripoli -- who believe they have no choice but to resist or face war crimes charges.

Whatever their numbers, they are well-armed and fighting is still raging on the three fronts.

In Bani Walid, the assault has been made more challenging by the high hills and deep desert valleys in an around the city, 90 miles (140 kilometres) southeast of Tripoli.

"The terrain has proven too difficult to overcome from the northern edge," Genouna told The Associated Press. He also blamed what he said was a lack of support from the military council as well as poor planning and shortages of ammunition.

He said the brigade will be leaving to the new front over the weekend. More than 30 fighters have been killed in the failed effort to take the city from the north.

Fighting continued there on Friday.

Smoke could be seen rising from Bani Walid after NATO warplanes were heard in the area. NATO is continuing to strike Gadhafi forces in an air campaign that began in March under a U.N. mandate to protect civilians.

"We are ready to fight, but frankly we don't have a leader to guide us when we enter (Bani Walid). We need a leader to give us instructions," complained fighter Ali Omran.

In Tripoli, dozens of residents gathered in the centre of the city to demand the National Transitional Council address the needs of those injured during the civil war, which began in February.

Protesters held aloft a giant new Libyan flag, chanted in support of the injured, and carried signs reading "Help our wounded."

Also Friday, hundreds gathered in Tripoli's Martyrs' Square to offer prayers for those still fighting supporters of the former regime.