Libyans have begun observances on the first anniversary of their uprising against Muammar Gaddafi, while interim leader Mustafa Abdel Jalil vowed to act firmly against further instability.The former rebels, 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.