Libyans have celebrated on the first anniversary of their uprising against Muammar Gaddafi, with the interim leader, Mustafa Abdel Jalil, pledging to act firmly against further instability.
The former fighters, who toppled Gaddafi last year with NATO backing, set up fresh checkpoints in the capital, Tripoli, on Thursday, as well as in Benghazi, the eastern birthplace of the uprising, and the western port city of Misrata.
The country's new rulers have not organised any official celebrations at a national level as a mark of respect for the thousands of people killed in the bloody conflict, which left about 15,000 people dead, according to the United Nations.
But spontaneous celebrations began nationwide in cities and towns, led by residents of Benghazi, the city which first rose against Gaddafi and his 42-year-old regime. Protests broke out in Benghazi on February 15 after the arrest of human rights lawyer Fathi Terbil, but the first widely recognised "Day of Rage" came on February 17.
"We have called in special forces from outside of Benghazi. Soon the roads heading to the square will be closed to vehicles," Omar Farraj, in charge of security for the Tahrir Square celebration in Benghazi, told the AFP news agency.
"We want to ensure that the celebrations are peaceful, and we have deployed the revolutionaries across the city."
Libyans have been on edge since Saadi Gaddafi, one of the slain leader's fugitive sons, announced from his residence in Niger that he could start a new uprising at any time.
Men, women and children came out on the streets of Tripoli, Benghazi, Misrata and other towns late on Thursday to begin the celebrations by setting off firecrackers and chanting slogans.
"I will fight with my body, heart and soul for our new Libya," said Mustafa Ahmed Ali, a young recruit of the new Libyan army, as he ran with about 100 comrades after passing a military training course in Benghazi on Thursday.
"Curly we are sorry!" shouted children dressed like angels in sarcastic reference to Gaddafi, who bore that nickname because of his distinctive locks, in a procession in Benghazi.
Benghazi residents will formally celebrate the anniversary later on Friday at a function expected to be attended by Abdel Jalil, the chairman of the National Transitional Council. Abderrahim El-Keib, the prime minister, and other dignitaries will join him.
Abdel Jalil warned on Thursday that the revolutionary spirit of Libya and its stability would not be compromised in any way.
"We opened our arms to all Libyans, whether they supported the revolution or not. But this tolerance does not mean we are incapable of dealing with the stability of our country," he said in a television address.
"We will be tough towards people who threaten our stability. The revolutionaries are ready to respond to any attack aimed at destabilising" the country.
Tripoli resident Naima Misrati said traffic police and former rebels were distributing leaflets, warning people against thinking of carrying out attacks, which said "We cannot bring back the buried man but we can send you to him."
"I have no words to describe my happiness. There is joy everywhere in Tripoli," she told the AFP news agency.
Militias still powerful
But one year after the uprising, Libya is struggling, attempting to tame independent armed groups and reassert the rule of law.
Al Jazeera's Tony Birtley, reporting from Tripoli, said militias posed a major problem and that many Libyans were yearning for justice.
"Militias are out of control and are very well armed," he said. "When I met the deputy prime minister he said 'you've got to understand our security is still in their hands. We need them for security'."
Hafed al-Ghwell, a World Bank adviser, said in a recent report: "By now [the militias] have developed vested interests [that] they will be loath to relinquish."
Global human rights organisations Amnesty International, Human Rights Watch and Doctors Without Borders have accused militias of torturing their prisoners, most of whom are former pro-Gaddafi fighters.
Keib has acknowledged that integrating rebel fighters is a "complex" issue. But his government on Thursday said that about 5,000 of them had so far been incorporated into official security services.
Ghwell said there were also concerns about the ruling NTC itself.
"The NTC has had to struggle with internal divisions, a credibility deficit and questions surrounding its effectiveness," he said.
The challenges are manifold, including rebuilding an aging and damaged infrastructure, fostering vibrant state institutions, tackling a corrupt economy and boosting what are weak health, judicial and educational systems.