Dhaka, July 10 -- Nigerian security forces have killed at least 30 gunmen in a joint military and police operation following a wave of violent attacks in the country's northwest, officials said Thursday.

The operation was launched on Wednesday in response to coordinated assaults by armed men on several villages the previous evening, according to a statement by Nasir Mua'zu, State Commissioner for Home Affairs. He confirmed that three police officers and two soldiers were killed during the counter-assault.

"We are working tirelessly with federal security agencies to ensure the safety of all citizens," Mua'zu said.

Violence has surged across northwestern and north-central Nigeria in recent months, with armed gangs-often referred to as "b...