Members of the Territorial Intervention force, a combined army-police unit, participate in a presentation ceremony prior to their deployment to deal with gang violence in violent areas, at La Campanera Neighborhood in Soyapango, El Salvador April 26, 2016. REUTERS/Jose Cabezas

SAN SALVADOR (Reuters) - Homicides fell sharply during April in El Salvador, police figures showed on Monday, after ferocious gang violence probably turned the poor Central American country into the world’s most murderous nation.

The violence has challenged the government of leftist President Salvador Sanchez Ceren, who has struggled to finance security plans and has instead focused efforts on controlling the more than 15,500 gang members locked up in 13 prisons.

Police measures to curb the gang warfare are paying off, said El Salvador’s police chief, Howard Cotto, with 352 murders in April, down 15.8 percent from the corresponding month in 2015, and nearly half the first-quarter monthly average.

The nation of about 6.4 million people registered 2,003 murders from January to March.

A 70 percent jump in homicides last year meant El Salvador probably displaced neighboring Honduras as the country with the highest murder rate - a ranking usually made on the basis of U.N. data published a year or two in arrears.

With about 6,600 murders in 2015, El Salvador’s murder rate exceeded 100 for every 100,000 inhabitants.

In Honduras, where the rate surpassed 85 for every 100,000 people between 2011 and 2012, the number had fallen to about 60 last year, preliminary police data show.

Despite April’s improvement, the outlook for El Salvador remains grim: murders were up 52 percent in the first four months of this year over the corresponding 2015 period, police data shows.

Violence cost El Salvador some $4 billion in 2014, or 16 percent of its national income, its central bank says.