Heavily armed gunmen of two rival militias have clashed in the Libyan capital Tripoli for hours, killing at least one person and injuring 12 others.

The fighting erupted on Thursday after militia chief Nuri Friwan died from injuries he sustained at a checkpoint controlled by former rebels from Soug al-Jomaa, an eastern Tripoli district.

To avenge his death, the militiamen from the city of Misrata travelled to the Soug al-Jomaa district of the capital and battled with the men with anti-aircraft guns and grenades across Tripoli.

In retaliation, the Soug al-Jomaa militiamen fired rocket-propelled grenades (RPGs) at the attackers.

At around 11:00 p.m. (2100 GMT), heavy shooting continued in Soug al-Jomaa and at least three other districts close to the foreign ministry, state television building and embassies.

Since the overthrow of long-time dictator Muammar Gaddafi in 2011, the Libyan government has been struggling to tackle the presence of armed militants, who fought against forces loyal to Gaddafi.

Libyans rose up against Gaddafi’s four-decade rule in February 2011 and deposed him in August 2011. He was slain on October 20 of the same year.

Benghazi was the birthplace of the 2011 uprising. It is largely governed by militias in the absence of unified Libyan security and military forces.

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

Meanwhile, a blockade by armed groups on key Libyan oilfields and terminals in the east has paralyzed the country’s oil industry, choking output to a tenth of normal levels.

Guards working with the oil industry have been on strike since July and imposed a blockade on oilfields and terminals. Many armed militants and defected soldiers have also joined the guards in their campaign against the government.

The Libyan government is importing fuel to keep power stations running and queues are growing at petrol stations across the country.

In an interview with Press TV last month, political commentator Johnny Miller said that Libya is on the verge of becoming a failed state.

Miller, who is a freelance journalist based in London, made the remarks on October 11, a day after armed militants abducted Libyan Prime Minister Ali Zeidan from a hotel in Tripoli, but freed him hours later.

Libya “really is close to being a failed state. I mean you have the situation where the government is very, very weak. You have the streets ruled by militias, affiliated with the government, but also acting unilaterally by themselves,” he said.