By Nelson Renteria
SAN SALVADOR, April 3 (Reuters) - The number of murders in the small Central American country of El Salvador rose 44 percent in the first three months of 2014 compared with the same period last year, leaving a two-year-old truce still in force between violent gangs hanging by a thread.
There were 794 murders from January to end of March, up from 551 over the same period last year, El Salvador's Institute of Legal Medicine said on Thursday.
It attributed the rise to increasingly tough police tactics against the violent street gangs that have run riot in the country for years.
More aggressive policing has squeezed the gangs' revenue sources, so they are increasingly battling each other for income.
"The police have taken a slightly stronger position of confrontation with the criminals, as it should be, but there has also been a response from the criminals," the institute's director, Miguel Fortin, told reporters.
The rise in murders comes two years after a truce between the Mara Salvatrucha (MS-13) gang and rival Barrio 18. The armistice, brokered by the Catholic Church and the Organization of American States, at first lowered the murder rate, the world's highest in 2011 at 66 per 100,000 inhabitants.
But by the following year, the truce, which never received a great deal of public support, appeared to be crumbling and the murder rate shot up.
"The truce never worked," said Fortin. "The murder rate fell but not the rate of violence."
Last month, leftist Salvador Sanchez Ceren of the ruling Farabundo Marti National Liberation Front (FMLN) was elected as the country's next president.
Fortin said the spike in murders was unrelated to the presidential race as outgoing President Mauricio Funes had alleged during the campaign. (Reporting by Gabriel Stargardter; Editing by Simon Gardner and Mohammad Zargham)