By Ghaith Shennib and Jessica Donati
TRIPOLI (Reuters) - A blast that killed three people in Libya's second city Benghazi was caused by fishing explosives that detonated accidentally, not a car bomb as originally thought, a local government official said on Tuesday.
But rights activists said the incident was symptomatic of deteriorating security in a country whose government exerts scant authority beyond the capital Tripoli.
The oil-producer is largely split into fiefdoms of armed groups that were instrumental in the 2011 revolution that ousted dictator Muammar Gaddafi and are now competing for influence.
"The vehicle belonged to a fisherman, who was killed in the blast caused by the explosive materials he was carrying in his car," Tarik Bozribe, a Benghazi city councilor, told Reuters.
The car blew up on Monday near a hospital in the city in eastern Libya, killing the three people, including a child, and injuring another 14, the Health Ministry said.
Libyan fishermen often use explosives to snare their catch.
"The root cause of the accident is the weakness of the state. There is no control, no army and no security," said activist Zeid Al-Ragas.
"These explosives are manufactured into bombs and thrown into the sea to catch many fish. A lot of people use it... The big question is: If fisherman can get these materials so easily, what sort of weapons can the militias obtain?"
In an example of Libya's disarray, the armed forces chief deployed troops to Benghazi and arranged for rebel brigades to reinforce them to keep the peace after the explosion.
A number were recalled over fears they would fight each other, but this decision was again reversed late on Tuesday.
Libya's president defended the decision, saying securing Benghazi was a task requiring the cooperation of different factions of the national army, the police and various, rival brigades.
"The security problem in Benghazi is different to any other city because of the many assassination attacks and the continuous explosions," Mohammed Magarief told a news conference.
The decision came in face of protests in various cities by citizens calling for the government to act decisively to dismantle the "militias" they say are at the root of the security problem in the first place.
However, Councilor Bozribe said the priority was to ensure citizens felt safe. "We don't care about the background of the troops that will secure the city, or whether they are part of the regular armed forces or militia," he said.
(Additional reporting by Feras Bosalum in Benghazi; Writing by Jessica Donati; Editing by Alison Williams)