El Salvador is to deploy more army patrols on the streets after the latest violence blamed on gangs.
El Salvador is believed to have more than 10,000 gang members
About 1,000 troops have already been deployed, but the government says more are needed following the murder of two police officers outside a night club.
Some 3,000 people have died in violence so far this year in El Salvador.
It is struggling to contain gangs, many of which originated in Los Angeles in the 1980s and spread to Central America after their members were deported.
The gangs, sometimes known as maras, are blamed for a wave of killings and robberies in El Salvador, Guatemala and Honduras.
There are believed to be more than 10,000 gang members in El Salvador.
Human rights groups say the Salvadoran government should invest more in anti-poverty programmes rather than relying on tough tactics.