As police Inspector Alba Guevara Lopez's officers fanned out through the narrow alleys of a gang-controlled neighborhood in this San Salvador suburb, half had their faces hidden by black ski masks.

"Those who live a little closer are scared that they might be identified and later face reprisals when they're off duty," said the 20-year veteran cop, her face visible behind a pair of sunglasses. "In your free time you become more vulnerable."

There is reason to be afraid. Hyper-violent gangs declared open-season on police in this Central American nation in response to a government crackdown that began last year. Killings of officers nearly doubled to more than 60 in 2015, and so far this year 15 officers have been slain, including two Tuesday. In some cases they are targeted while they're off duty and relaxing with family members, who also become victims.

Analysts say the growing attacks are a sign El Salvador's conflict is spiraling out of control and threatening to explode into open warfare.

"The gangs have managed to provoke a psychosis and paranoia within the police," damaging the force's already low morale, said Jeannette Aguilar, an expert on gangs who is director of the University Institute of Public Opinion at Central American University in San Salvador.

It's also part of a chain of eye-for-an-eye killings and retaliations that has put the country on a path toward far greater bloodshed, she said.

El Salvador had the world's highest homicide rate outside war zones in 2015, with 103 slayings per 100,000 residents. In the first three months of this year there have been more than 2,000 killings, putting it ahead of last year's pace.

The bloodshed has sent thousands of Salvadorans streaming toward the United States. Last week the U.N refugee agency called for immediate action to help those fleeing violence in El Salvador and neighboring Honduras and Guatemala in numbers not seen since the region was wracked by civil wars in the 1980s.

Aguilar sees 2015 as a watershed moment in El Salvador's violence as both the government and gangs pursued strategies of more open confrontation, and even ordinary citizens took up arms to hunt down gangsters.

Gangs set up training camps in the mountains and exploded a car bomb in the capital. They began targeting police and their loved ones as well as soldiers when the army became more involved in the fight.

In just three weeks in January, gang members were blamed in the slayings of a cop's father, a soldier's brother, the wives of two police officers, and a woman and her son who were relatives of a cop.

Last month, special forces soldier Carlos Enrique Ramos was slain along with three family members he was visiting in a rural area. They were found with hands and feet bound, their bodies riddled with bullet and machete wounds. Authorities said the Barrio 18 gang controls the area.

For Guevara, it's personal: Several of the inspector's colleagues have fallen victim to off-duty murders that she's sure were carried out by gangs. One officer was at home sweeping his patio, "totally relaxed." The other was fixing his roof.

"It wasn't coincidence. They (the gangs) had an objective," she said.

Marvin Reyes, another 20-year police veteran, said that by his count 13 officers and 25 of their relatives have been killed so far this year. That was before Tuesday, when authorities said Barrio 18 gunmen killed two officers in an attack on police escorting a witness. Six alleged gang members were killed.

Reyes said police earn so little they have no choice but to live in neighborhoods controlled by gangs they're combatting. Simply going home at night puts families at risk, so they often sleep at police stations. Many officers have abandoned homes they're still paying for to rent elsewhere. Many are leaving the force, in most cases to move to the U.S.

"We have to live together with the criminals. Our children go to the school where the criminals go. Our kids walk in the same places where the criminals' kids walk," Reyes said. "The gangs see that we're vulnerable when we're on leave, when we're not on duty."

Reyes and others have tried to organize to demand better working conditions and pay in a nation where the base police salary is $425 a month before taxes. But the law prohibits police from unionizing, and last month Reyes was suspended without pay along with five other labor-activist cops.

Justice and Security Minister Mauricio Ramirez Landaverde, who was national police director until January, acknowledged that security forces are vulnerable. He said the proper response is more training and, more importantly, taking down those responsible for attacks on police to show it won't be tolerated.

"Many criminal organizations have found that it is a way to maintain a kind of grip on the government, hoping that under this pressure the government will sit down with them," he said. "The government already clearly said that it is not going to do it, so that means there will be a period that's not only painful but hard in terms of work for the police."

The gangs ordered a unilateral cease-fire this month and the daily death toll dropped, but no one seems to think it will hold.

The government is taking an increasingly hard line. Last week authorities announced the transfer of 342 jailed high-ranking gang leaders to a maximum-security lockup where they will be held in isolation. Last week, President Salvador Sanchez Ceren called up 1,000 military reservists to join the fight.

Aguilar says provoking the gangs and eschewing dialogue ignores the fact that in many cases gang attacks are a response to alleged extrajudicial killings and other abuses by police.

It also risks ramping up the conflict into all-out war between gangs, security forces and civilians, she warned.

"This is going to generate an unstoppable spilling of blood in communities," she said.