Several technicians were injured when an adaptor exploded due to a technical fault during its maintenance in Taiz Province.
Head of the maintenance department in the provincial electrical office and four other fellows got minor and medium injuries in the explosion in Usaifra in Al-Qahera district.
On the other hand, an explosion was heard at the market in the area, with reports saying it was a sound grenade that hurt some people. The injuries were minor to medium, according to the reports.
The blast came a day after a gang attacked some stores, firing on and burning them.
The group members ran away and none has been arrested yet.
Eyewitnesses said exchanges of gunfire are common in the area where many people go shopping. Security was tight and an investigation is underway, officials said.
In Dhale Province, a garbage collector found an explosive device near the intelligence office in Al-Jalilah area. A security source was quoted as saying the female worker took the device to the office and she was investigated.
The investigation revealed she had nothing to do with it and she was released.
The incident came amid a series of attacks on offices of public security and intelligence in south and southeastern areas in the last few months.
It triggered fears of targeting security officials by bomb gift boxes, such as the last suicide attack on the provincial security office when a motorcycle that was carrying meals for a detainee exploded at the gate of the office injuring 9 policemen.