Gambia's police chief has announced that no further protests will be allowed in the West African nation without permits following recent street protests over prolonged power cuts during the hottest months of the year.

The protests highlighted public frustration ahead of presidential elections in December.

"From this very moment, nobody is allowed to protest without an approved permit," Seedy Mukhtar Touray, Gambia's inspector general of police, said in a statement late Thursday.

"Nobody is allowed to converge, cause havoc, distort the peace and tranquility of the nation, especially during the night. Any violation to this will be met with necessary force."

During the unrest earlier this week, a police post was vandalised and "detainees were unlawfully released from custody", Touray said, while the national utility, National Water and Electricity Company Ltd (NAWEC), said it had closed three branches after attacks severely damaged buildings, infrastructure and office equipment.

Arrests over vandalism

Authorities have arrested 11 people in connection with vandalism during the unrest, Touray said.

NAWEC said in a statement on August 15 that it was experiencing "an unforeseen surge in electricity demand during the peak period," which it attributed to high temperatures.

President Adama Barrow visited NAWEC facilities on Tuesday morning and promised that Gambia would receive new generators this week and restore electricity by the end of October.

He said the government was in the final stage of installing an additional 24-megawatt generation machine and that it awarded a contract for a 50-MW solar power plant.