Gunmen fired rocket-propelled grenades at the Tripoli headquarters of private television channel Alassema on Tuesday without causing any casualties, a station official said, in the second such attack in a week. The station's director Atef al-Ghanmi said attackers in a building across the street from Alassema fired the RPGs, damaging the channel's headquarters. Guards opened fire at the group, forcing them to flee, he added. The attack is the latest in a string targeting media outlets in Libya, where private networks and newspapers have sprung up in the aftermath of the 2011 uprising that ousted and killed dictator Moamer Kadhafi. It came a day after Libyans marked the third anniversary of the uprising in the north African nation, which has been plagued by political tensions and violence. Much of the unrest has been blamed on Islamists repressed by the Kadhafi regime and ex-rebels who helped topple the strongman, but now defy Libya's interim rulers as they struggle to restore law and order. Ghanmi said no one was hurt in the attack, the second since last Wednesday, when three RPGs slammed into the headquarters of Alassema, wounding a guard. The channel is known for its anti-Islamist stance and has been accused by Islamists of urging people to demonstrate against the General National Congress, Libya's top political authority. Many Libyans accuse the GNC of corruption, power grabbing and failing to stop the country's slide into chaos. The latest attack also comes as Libyans prepare to elect a panel to draft a new constitution on Thursday. But the GNC has agreed to hold early polls to elect new transitional authorities rather than wait for the constitution to be finalised. Thousands of Libyans have taken to the streets in recent weeks to protest against a GNC decision to extend by 10 months its mandate, which was originally due to expire on February 7.