Fresh clashes have erupted in a Tripoli suburb as the death toll from violence that followed a protest against armed groups rose to at least 43.

Saturday's gun battles broke out to the east of the capital in Tajoura, where rival gunmen clashed at checkpoints set up to stop more gunmen nearby city of Misrata from entering Tripoli, Mohammad Sasi, a local member of Libya's congress said.

Eight pro-government fighters were wounded, the official LANA news agency reported.

Tripoli is on edge after other Misrata militiamen in Tripoli opened fire on Friday on protesters demanding the disbanding of unlawful armed groups, killing 43 people and wounding 400, LANA reported the Interior Ministry as saying.

Soldiers and government-affiliated militiamen were trying to regain control of a base attacked on Friday evening by militiamen coming from Misrata.

Many stores in the city were closed on Saturday. Tripoli officials have declared a three-day mourning period.

The new clashes occurred despite Prime Minister Ali Zeidan urging the rebels to stay out of Tripoli, saying that "it would have negative and catastrophic consequences".

Also on Saturday, security was tight around Tripoli due to funeral processions for those killed on Friday.

The fighting followed demonstrations on Friday, in which imams, during weekly Muslim prayers, called for protests against armed groups and former fighters who refuse to disarm, which then degenerated into deadly clashes continuing through the night.

The demonstrations on Friday were the biggest show of public anger over the out-of-control fighters.

After the death of longtime dictator Muammar Gaddafi in 2011, Libya's new leaders have struggled to take control of armed groups fighting over power and influence.