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Jittery last-minute Christmas (search) shoppers scurried for cover at rumors of Mara street gangs gathering for battle one day after gunmen shot up a bus, killing 28 people in a gruesome massacre.

One of the more than 1,000 officers patrolling the outskirts of this city Friday said the panic may have been caused by some fireworks — a Christmas tradition here — that the crowd thought were gunshots.

"I was buying some shoes when somebody shouted, 'Here come the Maras.' And everybody started running," said shopper Norman Moreno. Sobbing women and crowds of men scurried for cover. Police cars hurried to the scene but failed to find the cause of the panic

Thursday's massacre has made Honduras' (search) anti-crime campaign seem more like an open war between street gangs and authorities, with the soldiers patrolling the outskirts and police searching slum neighborhoods for the killers.

The assailants stuck a message to the windshield of the bus, claiming 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,

The note promised more violence, saying "people should take advantage of this Christmas, because the next one will be worse" and included threats against congressional President Porfirio Lobo Sosa (search), a death penalty supporter, and candidate for the 2005 presidential election. Capital punishment was abolished in the 1950s.

Lobo Sosa told reporters at a morgue where victims were taken that the attack "just reinforces my view that we have to revive the death penalty." He also visited the scene of the attack.

"This is a desperate act by the criminals in response to our struggle against them, but we will not retreat," President Ricardo Maduro said. "These evil man seek to intimidate us and destabilize the country, but they will not be able to."

Maduro has waged a zero-tolerance campaign against the gangs, and at his bidding Congress approved a law in August 2003 that sentences gang members to up to 12 years in prison. Gang members have responded with more violent attacks.

San Pedro Sula has been a hotbed of gang violence and was the scene of a deadly fire that killed over 100 gang members at a local prison in May.

In Thursday's massacre, assailants cut off the city bus that carried 53 Christmas shoppers, then opened fire in the San Pedro suburb of Chamelecon, 125 miles north of the capital, Tegucigalpa, in the worst violence in years in a country known for lawlessness. Twenty-eight people died, their bodies littering the muddy dirt road. Fourteen were wounded, and 11 escaped unharmed or with light wounds.

"People kept screaming, and the shooting continued for what seemed like 15 minutes," said survivor Glenda Ramos, recovering in a hospital from wounds to the chest and shoulder.

"I threw my boy to the floor (of the bus) and covered him with my body," said Ramos, 22, describing how she saved her 3-year-old.

A suspected gang member was later arrested carrying several automatic weapons and driving a car spotted at the scene.

Honduran gangs claim more than 100,000 members and control poor neighborhoods in the country's major cities, where they are known for extorting "protection" money from residents as well as committing crimes.