El Salvador's government will not negotiate with powerful street gangs following an anonymous offer to stop crime-related bloodshed afflicting this Central American country, the head of national police said Monday.

"There is no negotiation of any kind with any criminal structure," police commissioner Howard Cotto said at a news conference. "Our job is to prevent and combat crime, that is what we do and that is what we are going to continue doing."

Cotto's comments came in response to a video circulated over the weekend in which three masked men saying they represented the country's three major gangs said they had ordered a stop to killings. They asked the government in exchange not to institute measures being considered to combat them.

"We have ordered all of our people ... to halt all types of homicides nationwide to demonstrate to the public, the government and international agencies in our country that there is no need to implement measures that only violate our constitution," one of the masked men said.

Presidential spokesman Eugenio Chicas said Sunday through his Twitter account that the government would not let up in its pursuit of the gangs.

"This administration will not grant any truce in the fight against criminals, and will apply the necessary measures to protect the population," Chicas said.

According to official statistics, at least 6,657 people were killed last year in El Salvador. The overall annual homicide rate last year was around 103 per 100,000 inhabitants.

The homicide rate fell dramatically in 2012 during a previous truce with gangs, but violence spiraled to new heights following its dissolution.