Tripoli, Libya (CNN) -- Armed men attacked the Tripoli headquarters of a privately owned Libyan television channel early Wednesday, causing extensive damage to the building, al-Asema TV reported.
At least seven masked men attacked the station just after midnight with small arms and rocket-propelled grenades, causing heavy damage to the building and broadcasting equipment and setting part of it on fire, the station reported.
The gunmen made the staff leave the building first, the station said.
Al-Asema TV is a privately owned channel affiliated with Mahmoud Jibril, the country's interim Prime Minister during the 2011 revolution, and his National Front Alliance (NFA), the liberal political bloc in the General National Congress, Libya's parliament.
The channel is viewed as critical of Islamist parties in Libya especially now, during a time of heightened political polarization in the country.
The attack was the latest in a wave of violence targeting Libyan media.
Earlier this month, an armed attack on Libya al-Ahrar TV in the eastern city of Benghazi damaged the building and broadcast equipment.
And this week, four Libyan journalists were kidnapped in two separate incidents in Tripoli, said Reporters Without Borders (RSF).
One, the editor of a state-owned newspaper, was released on Tuesday. He had been abducted from outside a cafe in central Tripoli a day earlier.
The other three -- all of them state television employees -- remain missing.
It's not clear who is behind the kidnappings.
In a statement Wednesday, RSF condemned what it described at "the steadily mounting violence against media personnel in Libya."
"Reporters Without Borders is extremely worried by the situation in Libya three years after the start of the uprising against the Gadhafi dictatorship and urges the authorities to do everything possible to improve the environment in which the country's journalists work," the group said. "It is in every Libyan's interest to ensure that media personnel can work safely, without fear of being threatened, attacked, kidnapped or murdered."
The security situation has been deteriorating in the North African country, with Libya's weak central government unable to rein in militia groups with different regional, tribal, ideological and political loyalties. The government has been struggling with its plans to build an army and police.
According to RSF's 2014 Press Freedom Index, Libya dropped six places and is now ranked 137th out of 180 countries.
"In Libya, freedom of information is under threat from the violence that continues to rock the country," the group said. "Working as a journalist is still very arduous nearly three years after the February 2011 uprising against the Gadhafi regime, which used strict media control to hold on to power for more than four decades. The enthusiasm generated by the Libyan 'media spring' is running out of steam."