Just over a year ago, Bukele launched a controversial "war" on gangs in which more than 68,000 suspected gang members have been arrested without a warrant under a state of emergency.

The police officer was killed Tuesday in Nueva Concepcion, a town of 30,000 people in the Chalatenango department some 80 kilometers (50 miles) north of the capital, San Salvador.

"We established a security cordon around the municipality of Nueva Concepcion, Chalatenango, with more than 5,000" members of the armed forces and 500 police officers in a bid to catch those responsible for the killing, Bukele wote on Twitter.

The operation began at dawn, with security forces searching homes and asking passersby to show identity documents, local media said.

Bukele said the hunt was on for the alleged killers but also "the entire structure of gang members and collaborators who are hiding there."

Gang members would "pay dearly for the murder of our hero," police officer Maximino Antonio Vasquez, he added.

The national police force said Vasquez had been patrolling with other officers when he was attacked.

He was the fourth police officer killed since Bukele launched his war on gangs in March 2022, and the first this year.