SAN SALVADOR, El Salvador - Prosecutors in El Salvador announced Friday they have arrested five police officers, 16 gunmen and a police administrative employee for allegedly killing street gang member and others.

There have long been reports of death squad-style killings in El Salvador, where street gangs have been battling police, boosting the country's murder rate to 103 homicides for every 100,000 residents last year.

Douglas Melendez, the country's attorney general, said Friday the gang arrested this week appears to have been dedicated to crime in general, including murder for hire and robbery.

Melendez said "an isolated group" of police officers appears to have co-operated with the gang since 2015 by providing information or vehicles to the killers. The group has been implicated in about 11 homicides.

Police commissioner Howard Cotto said the arrested officers participated directly in some killings and loaned weapons or uniforms used in other homicides.

In some cases, the uniforms allowed killers to approach victims or remove them from their homes more easily.

"They were not just interested in killing people for belonging to gang groups, but also for personal interests, for someone who paid to have someone killed," Cotto said.

Raids turned up 17 police uniforms and one from the military and about a dozen guns.

Miguel Montenegro, the head of the country's Human Rights Commission, said that death squads have operated in El Salvador, adding "this is why we should strengthen our justice system."

The Salvadoran government has embarked on a tough crackdown on gangs, which have in turn launched attacks on police and military officers, even when they are off duty.

In April, El Salvador's human rights prosecutor said police and soldiers used excessive force or executed presumed street gang members during two supposed confrontations in 2015.

One case involved the deaths of eight people in March 2015 at a ranch supposedly taken over by gang members. Only one officer was slightly wounded.

The other case occurred in August 2015, when five gang members died in a supposed shootout with security forces, none of whom were injured.

Human rights prosecutor David Morales said there was "serious, objective, clear evidence that points to executions" of the suspects in both cases.

News from © The Associated Press, 2016