BENGHAZI, Libya (Reuters) - Sporadic explosions and heavy gunfire broke out in central Benghazi at around 10 p.m. (2000 GMT) and lasted about 40 minutes, a Reuters witness reported from the city.
The Libyan government had earlier said its forces would observe an immediate ceasefire in their battle against anti-government forces from 1900 GMT.
Western powers have been bombarding Libya since Saturday in an attempt to protect civilians in rebel-held areas, especially the rebel stronghold of Benghazi, from attacks by Libyan government forces.
Intense small arms fire and heavy explosions continued in central Benghazi until about 2040 GMT.
Gunmen were firing across streets around the al-Noura hotel. One group set up a roadblock in the street.
Residents had expressed fears that infiltrators loyal to Libyan leader Muammar Gaddafi were still in the city, despite the retreat of the main armed force attacking Benghazi after it was bombarded by Western air strikes.
(Reporting by Reuters staff; Writing by Kevin Liffey)