Honduras' (search) security minister pledged on Monday to eliminate violent youth gangs, nine of whose members have been charged with homicide in connection with a Dec. 23 shooting attack on a public bus that killed 28 people.

The investigation of Thursday's violence has focused on suspected Mara Salvatrucha (search) gang member Alex Ramirez, 23, who was captured shortly after the attack driving a car whose interior was stained with blood, and carrying two assault rifles, two handguns and ammunition.

Authorities arrested eight others during a major sweep in the days following the attack, which occurred on the outskirts of the northern city of San Pedro Sula, 125 miles north of the capital, Tegucigalpa.

President Ricardo Maduro (search) this week accused the ruthless street gang of having "planned the massacre to frighten my government, which has had success in fighting crime."

In a message left on the bus's windshield, the gunmen claimed they were part of a previously unknown revolutionary group opposed to the death penalty, one of the main campaign issues in next year's presidential campaign. Executions were stopped in the 1950s.

They also left a threatening message against the president of Congress, Porfirio Lobo Sosa, who is a death penalty supporter and one of four contenders for the ruling National Party's presidential nomination.

Security Minister Oscar Alvarez pledged on Monday to eliminate the violent gangs.

"We will not rest until we eliminate the gang members from Honduras, because the public is angry and indignant," Alvarez said as he announced an increase in the number of army troops assigned to patrol the nation's streets.

Honduran youth gangs, known as "maras," claim more than 100,000 members and control poor urban neighborhoods, where they are known for extorting "protection" money from residents and other crimes. Many of the groups began on the street of Los Angeles and spread to El Salvador and Honduras after members were deported back to those countries.