A man is taken into custody by FBI agents on May 17 in Los Angeles. Hundreds of federal and local law enforcement fanned out across Los Angeles, serving arrest and search warrants as part of a three-year investigation into the violent and street gang MS-13. (Jae C. Hong/AP)

The Trump administration’s push to deport more Central American gang membershas alarmed officials here who fear that the returning gangsters could exacerbate violence in one of the deadliest countries in the hemisphere.

This year the U.S. government has deported 398 gang members to this country, compared with 534 in all of 2016, according to Salvadoran government statistics. This sharp increase in the rate of gang deportations — and the prospect of more gang roundups in the United States — has prompted Salvadoran authorities to hold emergency meetings and propose new legislation to monitor suspected criminals who are being sent home.

“This clearly affects El Salvador. We already have a climate of violence in the country that we are combating,” said Héctor Antonio Rodríguez, the director of the country’s immigration agency. “If gang members return, of course this worries us.”

In tweets and speeches, President Trump has made MS-13, or Mara Salvatrucha, the leading symbol of the dangers of illegal immigration and the need for more and faster deportations. He has compared the gang’s “meanness” with that of al-Qaeda. He promised last week that the organization will be “gone from our streets very soon, believe me.” Recent high-profile killings, such as that of a 15-year-old Salvadoran girl in Springfield, Va., and a string of slayings on Long Island, have fueled concerns of an MS-13 resurgence in the United States.

In El Salvador, this gang and rivals such as the 18th Street gang have terrorized neighborhoods for decades. MS-13 formed in Salvadoran immigrant communities in Los Angeles in the 1980s, building its ranks with refugees from the country’s civil war. Waves of deportations over the years helped MS-13 take root in El Salvador and grow into a powerful criminal organization with tens of thousands of members across Central America.

(Claritza Jimenez/The Washington Post)

Since President Salvador Sánchez Cerén took office in 2014, the Salvadoran government has been on a warlike footing against ­MS-13 and the 18th Street gang. Authorities have deployed thousands of extra police officers and soldiers to hunt down gang members and limited access to prisons in an effort to stop gang leaders from using visitors to relay orders to members on the outside. Police and soldiers have regularly been accused of human rights violations and extrajudicial killings during this offensive.

Salvadoran authorities think they have slowly been making progress. The number of homicides, which peaked in 2015 at more than 6,600, dropped by 20 percent last year and has continued to fall. Even so, El Salvador has one of the highest homicide rates in the hemisphere and gangs regularly prey on communities, kidnapping residents and demanding extortion payments.

Law enforcement officials in Los Angeles and other U.S. cities have launched raids recently to capture dozens of MS-13 and other Latino gang members. U.S. Immigration and Customs Enforcement announced this month the arrest of more than 1,300 gang members across the country in what it described as the largest anti-gang crackdown in agency history.

Salvadorans are dreading the return of those captured in the U.S. raids.

“Probably we won’t feel the symptoms today or tomorrow or the next week. But probably in six months or a year we’ll be feeling the symptoms of what these deportations are causing now,” San Salvador Mayor Nayib Bukele said in an interview.

Gang members make up a small fraction of the deportee total. Salvadoran authorities say 6,922 people were brought back here from the United States in the first four months of the year, up slightly over last year.

This year the total number of deportations by United States has dropped about 12 percent, to around 56,000 people, compared with the same period last year. Officials have attributed the decline to the fact that the federal immigration court system is overtaxed.

But the Trump administration is clearly working to expel more gang members.

“You know about MS-13?” Trump said during a speech in April to the National Rifle Association. “Get them the hell out of here, right?”

Salvadoran officials worry that although the number of killings has fallen this year, gangs could quietly be strengthening or reorganizing. MS-13 has at least 49 “cliques” in El Salvador, according to Guadalupe de Echeverría, the head of the homicide and anti-gang unit at the attorney general’s office. Over the years, some of these cliques have named themselves after the cities in the United States where members lived before being deported.

One important dynamic within MS-13, Echeverría said, is a recent rupture between the historic leaders, most of whom have long been imprisoned, and an offshoot known as the “503” — the telephone country code for El Salvador.

“They have already formed a new group, and very probably with deported people,” she said. “We’ve already seen a certain amount of violence between them.”

To prepare for moredeportations, the Sánchez Cerén administration recently proposed legislation to monitor gang members who return to the country. Under the measure, if the suspected gangster had no warrant for crimes in El Salvador, he would be asked to check in with police once a month and notify authorities whether he moved. The law also would create “internment centers,” possibly guarded by the military, that would be something like a halfway house for returning gang members.

Rodríguez, the head of the immigration agency, said that many gang members in the United States had fled conflicts with rivals in El Salvador.

“To return,” he said, “some run the risk of danger for having escaped. That’s why we think there is an opportunity in the internment centers to protect them and be able to reinsert them into society.”

Human rights workers here have questioned the legality of holding suspected gang members if they have not been charged or convicted of a crime in their home country.