The sister of Alberto Hernández Escalante mourns over the body of her brother, found in a clandestine grave near Caserio el Chumpe, El Salvador. Killings spiked by nearly 70 percent in the country in 2015. (Manu Brabo/AP)

MEXICO CITY — With more than 6,600 homicides last year in a population of 6 million, El Salvador has surpassed its violent neighbors and seized the unfortunate title of the hemisphere’s murder capital, according to police statistics, a situation that has contributed to a mass migration to the United States.

After a truce between El Salvador’s two most powerful street gangs — Mara Salvatrucha and the 18th Street gang — crumbled in 2014, the death toll has spiked to the highest levels since the country's civil war ended in 1992. The 2015 murder rate of about 104 homicides per 100,000 people, an increase of about 70 percent from the year before, is estimated to be among the highest in the world for countries not at war, far surpassing neighboring Honduras, which had held the title of murder capital in recent years.

El Salvador’s police have responded aggressively to the fighting between tens of thousands of gang members, with a crackdown involving neighborhood raids and arrests. But this has fueled more violence. The leftist government of President Salvador Sánchez Cerén, who was a guerrilla commander during the civil war, has opposed negotiations and moved gang leaders into tighter-security prisons, moves that have intensified the climate of confrontation.

“The government’s hard-nosed, hard-fisted approach to this has certainly fanned the flames that were already there,” said Eric Olson, a Central America expert at the Woodrow Wilson Center in Washington. “The question for me is: At some point, will one side prevail? Will the government succeed in repressing its way out of this problem. I find that hard to believe.”

Experts say violence is one of the main reasons that migrants are fleeing El Salvador and neighboring countries such as Honduras and Guatemala. In 2014, thousands of unaccompanied children from the region streamed to the U.S. border, overwhelming authorities. Those numbers have spiked again in recent months — in October and November, more than 10,500 children, the vast majority from those three countries, got apprehended illegally crossing the U.S.-Mexico border.

In December 2014, the State Department created a program under which minors from El Salvador, Honduras and Guatemala could apply in their home countries to be refugees in the United States and avoid the dangerous journey through Mexico. As of November, more than 5,100 of the nearly 6,000 applications have come from El Salvador, although just 16 of them have been approved, according to department figures.

The murder rate, more than poverty or health or education statistics, carries particular political weight for this cluster of small Central American countries known as the Golden Triangle. The number is tracked daily in newspapers and debated by politicians. The countries' murder rates have been among the top five in the world. But El Salvador surged to new heights last year, far surpassing its 3,942 homicides in 2014, a level its forensic medicine director, Miguel Fortin Magaña, described to Reuters as “truly pandemic.”

Homicides have been falling in Honduras, and President Juan Orlando Hernández this week touted that decline. "Honduras is no longer the first, nor the second, nor the third, nor the fourth, nor the fifth most violent country in the world," he said.

Honduras's murder rate was 57 homicides per 100,000 people. A Honduran police spokesman noted that even though there were 844 fewer homicides in 2015 than in the previous year, "the government should not forget that this statistic at the end of the year is 10 times higher than the world average and four times the average in the Americas."

The violence in El Salvador has been marked by gang factions and cells battling for supremacy, in addition to mounting attacks on police. César Ortega, who last year led an anti-gang division in the national police force and is now a local government official in San Salvador, said by phone that the gangs are trying to bend police to their will with the violence.

“The gangs are exerting pressure on the government to accede to their demands,” he said. “That’s what they’re trying to do by increasing the incidence of homicides in certain parts of the country.”

Ortega said the government should redouble its efforts and boost its intelligence capacity to take on the gangs. “We need to have a closer relation with the people, and not just tactically, to recruit people,” he added. “If the people have more confidence in us, we can provide them better security.”

Amid the rising violence in Central America, the Obama administration launched immigration raids over New Year's weekend, arresting at least 121 adults and children who were in the United States without documentation for deportation, according to the Department of Homeland Security. Critics of this approach believe it is dangerous to deport people who are fleeing such violence.

"Clearly there is a humanitarian crisis in El Salvador," said Alexis Stoumbelis, executive director of the Committee in Solidarity with the People of El Salvador. "It's unconscionable to send people back into the same situation."

Gabriela Martinez contributed to this report.