Dozens of protesters have stormed Libya's interim parliament building in Tripoli, with some of them rampaging through the building, witnesses have said.

According to the witnesses, the demonstrators entered the General National Congress (GNC) on Sunday and called for its dissolution, AFP reported.

They also demanded the release of demonstrators detained on Saturday night, when gunmen apparently with links to the GNC attacked the protesters and took them to an unknown location.

The protesters were holding a sit-in outside the parliament building.

According to authorities, two lawmakers were shot and wounded by the protesters who raided the parliament.

"Two (GNC) members were hit by bullets when they tried to leave the venue in their cars," Nuri Abu Sahmein, the speaker, said.

The GNC has stirred public anger by extending its mandate, which was due to expire in early February.

Libya has been witnessing numerous clashes between government forces and rival militia groups, who played a key role in the 2011 popular uprising that toppled former dictator Muammar Gaddafi.

The former rebels refuse to lay down arms despite efforts by the central government to impose law and order.