Two powerful explosions went off near the courthouse in Libya's second city of Benghazi, wounding 13 people, security and medical sources said.
The blasts came a day after more than 1,000 inmates escaped during a prison riot in the eastern city, birthplace of the 2011 armed uprising that ousted and killed dictator Moamer Kadhafi.
Mohamed Hijazi, spokesman for the security services in Benghazi, said two suitcase bombs had caused the blasts.
They went off as people gathered to break the Ramadan fast.
Initial reports from security officials spoke of 10 people injured, but a medical source at al-Haouari hospital later updated that to 13.
Local residents told AFP that nearby buildings were badly damaged in the blast.
Amid a spate of incidents in the restive city, nearly 1,300 inmates escaped during Saturday's riot in Benghazi's Al-Kuifiya prison, a security official said.
On Friday night, hundreds of protesters took to the streets of Benghazi to condemn the assassination in the city earlier the same day of Abdessalem al-Mesmari, an anti-Islamist lawyer who campaigned for a civil state.