Armed groups attacked military posts in Libya's second city Benghazi with bombs and a rocket-propelled grenade last night, an army commander said.

Nearly two years after the uprising that ended Muammar Gaddafi's 42-year rule, the government still exerts little control over the armed brigades that helped overthrow him.

Oil-producer Libya is largely split into fiefdoms of such brigades that are competing for influence.

No one was hurt in the four overnight attacks on three Benghazi army posts, said the military commander, Hamed Belkhair. Homemade bombs were thrown in three of the attacks and a rocket-propelled grenade was fired in the fourth, he said.

The army had sent extra forces to the eastern city after a car laden with explosives blew up near a hospital there on Monday, killing three people. Attacks on police stations have become a frequent occurrence in recent weeks.

"The national army is being subjected to these attacks because they are doing a great job of cleaning the city of criminals' shelters," said Belkhair.