Revenge among street gangs, despite a truce signed nearly two years ago, has increased violence in El Salvador over the past few weeks, the country's justice minister acknowledged Tuesday.

Ricardo Perdomo also said, however, that "many" recent murders have been the work of other criminal elements.

Between Jan. 1 and March 2, the number of homicides has soared to 501, an increase of 106 murders over the same period in 2013, national police director Rigoberto Pleites said Monday, adding that the truce between gangs "technically no longer exists."

"The report we have is that this resurgence of homicides has two fundamental causes, one of which is the war between the gangs" Mara Salvatrucha and Mara 18, Perdomo told reporters.

He said that certain gang crimes perpetrated recently "have sparked a wave of revenge: 18 attacks, MS fights back, creating a vicious circle of vengeance within their existing conflict.

Perdomo let it be known that the government will boost security measures in response to the resurgence of homicides and, particularly, with a view to the second round of the presidential election next Sunday.

Last year there were 2,492 homicides, 102 fewer than the 2,594 in 2012, according to figures from the medical examiner's office. EFE