At least one person has been killed in overnight fighting in the eastern Libyan city of Benghazi, hours after explosions rocked the city in attacks on buildings used by the judiciary, a security official said.

The clashes erupted in the western Gwesha district between an armed group and military special forces on Monday, as an upsurge in violence in the eastern Libyan city since last week's killing of a prominent political activist showed no signs of abating.

"Clashes broke out between special forces and an unknown armed group," Mohammed al-Hijazy, a spokesman for Benghazi security operations, said.

"At least one soldier was killed. The special forces have now retaken control".

Hundreds of demonstrators also gathered in Benghazi's streets denouncing the latest violence, according to residents.

Judicial buildings attacked

The clashes came after two blasts targeting judicial institutions in the city left at least 13 people wounded on Sunday.

Both blasts happened around the time families were breaking their Ramadan fast.

Residents living near the court said the building, and others nearby, had sustained significant damage. Windows were blasted out and rubble was scattered on the ground.

Suleiman El Dressi, a Libyan journalist, told Al Jazeera that authorities had begun their investigation at the scene.

"The attorney general has ordered prosecutors and [the] security apparatus to move to the scene and start investigations. Security sources say a security meeting is taking place in a military base at Benghazi," he said.

It was unclear who was responsible for the attacks.

The cradle of the 2011 uprising against Muammar Gaddafi, Benghazi has in the last three days witnessed explosions, assassinations, violent demonstrations and a mass jail break.

On Saturday, 1,117 prisoners escaped from Kuafiya prison following a riot and an external attack on the prison.

Authorities said that more than 100 of those who had escaped had been recaptured.

Armed violence and lawlessness, caused in part by often uncontrolled fighter groups, has hobbled governance in large areas of the oil-producing North African state following the 2011 war that toppled Gaddafi.

Source: Al Jazeera and agencies