The head of the National Transitional Council has delivered his first speech in Libya's capital, Tripoli, since the ousting of Muammar Gaddafi.
Mustafa Abdul Jalil outlined his plans to create a modern democratic state based on "moderate Islam" to thousands of flag-waving supporters in the newly renamed Martyrs' Square.
Earlier, Col Gaddafi vowed in a TV message to fight "until victory".
The whereabouts of the 69-year-old fugitive leader remain unknown.
"All that remains for us is the struggle until victory and the defeat of the coup," Col Gaddafi was cited as saying in a statement read out by a presenter on a loyalist television station.
Although the interim administration has promised the formation of a transitional government in Libya within 10 days, there are still big challenges in stabilising the country, says the BBC's Peter Biles in Tripoli.
Anti-Gaddafi forces now control most of Libya but loyalists are still holding out in the towns of Sirte and Bani Walid, offering fiercer resistance than had been expected.
Meanwhile, Amnesty International has called on the NTC to take steps to prevent human rights abuses by anti-Gaddafi forces.
'You are our weapon'
In his first speech since moving to the capital from the NTC stronghold of Benghazi, Mr Jalil told some 10,000 supporters to avoid retribution attacks, adding that Libya's new leaders would not accept any extremist ideology.
"We are a Muslim nation, with a moderate Islam, and we will maintain that. You are with us and support us - you are our weapon against whoever tries to hijack the revolution," he said.
Mr Jalil, who served as Col Gaddafi's justice minister before joining the rebels when the uprising started, said women would play an active role in the new Libya, and thanked a number of nations - including France and Britain - for supporting the NTC.
But he also warned against secularism, envisaging a state "where sharia [Islamic law] is the main source for legislation".
His words, broadcast live on television, were met with rapturous applause, as fireworks illuminated the Tripoli waterfront.
But Mr Jalil and his colleagues still face major hurdles, adds our correspondent, not least because the fugitive leader remains at large.
Many of his inner circle have fled to neighbouring countries such as Algeria or Niger.
Niger's Prime Minister Brigi Rafini said on Monday that Saadi Gaddafi and three of his father's generals were among 32 people who had crossed the lengthy desert border into the West African nation since 2 September.
The NTC has also to quell Gaddafi loyalists who are holding out in the last bastions of support for the fugitive leader inside Libya.
Fighting in Bani Walid south-east of the capital was halted on Monday, with one commander telling the BBC they were waiting for Nato war planes to continue air strikes targeting heavy weapons being used by pro-Gaddafi forces inside the town.
Late on Monday, hundreds of anti-Gaddafi forces had reportedly entered the town through its northern gate - only to be confronted by a barrage of rocket fire and bullets from snipers.
While flat-bed trucks carried fighters down the desert road towards the front line, a few cars sped in the opposite direction, carrying families fleeing the besieged town.
Residents said food and fuel supplies were running short in the town.
Fifteen guards were also killed when pro-Gaddafi forces attacked an oil refinery near the town of Ras Lanuf.
'Disappearances and torture'
In its latest report, Amnesty International says that while the bulk of violations were carried out by loyalist forces, anti-Gaddafi fighters have also been involved in torture and revenge killings.
Amnesty said a full picture had yet to emerge, but said it had asked Libya's opposition leadership to take steps to rein in its supporters and investigate any abuses, and to combat xenophobia and racism.
"The NTC is facing a difficult task of reining in opposition fighters and vigilante groups responsible for serious human rights abuses, including possible war crimes, but has shown unwillingness to hold them accountable," says the report - entitled The Battle for Libya - Killings, Disappearances and Torture.
Mohammed al-Alagi, a justice minister for Libya's transitional authorities, said the rebels had made mistakes, but said these could not be described as war crimes.