Salvadoran Attorney General Luis Martinez said Tuesday that authorities had captured a group of gang members who were preparing an attack with explosives on him and other government institutions.

"We have captured during the weekend suspects who were preparing C4 and dynamite explosives for an attack on the attorney general and government institutions," Martinez said. "This reaffirms the serious threat posed by these gangs."

He did not reveal details of the capture or identify the gang members, but said the investigation was receiving support from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives. He said they were still searching for the explosives.

The announcement of the plot came one day after the country's supreme court declared the gangs and their supporters to be terrorist organizations after rejecting constitutional challenges to the Special Law Against Terrorist Acts.

Unlike the criminal code, which does not include the crime of terrorism, by declaring the gangs to be terrorists, their members and supporters could face much more severe sentences.

Martinez said that under that law, maximum sentences for some crimes could increase significantly. It could also lead to extraditions to the United States in some cases, he said. Prior to the court's ruling some judges had disagreed with the law and did not apply it.

After weeks of spiraling gang violence, residents reacted positively to the court's ruling.

"This situation is unbearable," said Maria Teresa Sanchez, the owner of small business in the historic center of San Salvador. "Throw criminals in prison and that way we can live in peace."

The court's order also appears to close the door to any negotiations with the gangs. The recent wave of violence was interpreted as a way to pressure the government to reopen talks with the gangs, which the government had already ruled out.