Dozens of factories remained shut down and soldiers patrolled pipelines on Wednesday, a day after leftist rebels announced that they were behind the explosions that crippled the flow of natural gas to several large Mexican cities.
The country's airwaves were filled with news about the attacks. Leaders in Congress criticized President Felipe Calderon for not informing the public of the bombings until after the rebel group, the Popular Revolutionary Army, took responsibility on Tuesday for the unexplained explosions that day and on July 5.
Calderon again denounced the violence. "What we should do is set aside differences and attend to social needs through dialogue," he said in a speech on Wednesday morning at a signing ceremony for the first stage of a commuter railroad project. "There are others that dedicate themselves to destroying what we have all built."
The rebel group said in its communique that it had blown up two 36-inch natural gas pipelines supplying Queretaro, Salamanca and Guanajuato as part of a campaign "against the interests of the oligarchy and of this illegitimate government."
The group also demanded the release of two of its members, who it maintains disappeared on May 25 in Oaxaca, the scene of many violent anti-government protests last year. State and federal officials insist the men are not in custody.
The attacks have added to public jitters in Mexico, which has had an unprecedented wave of drug-related violence in the last two years and a close, polarizing presidential election last year in which the leftist candidate never conceded defeat.
"What these types of actions show is how easy it is to paralyze the country with a few people and get a lot of attention," Ana Maria Salazar, an author and radio host who has written about security threats in Mexico, said in an interview.
Why the Popular Revolutionary Army, a Marxist rebel group with roots in Guerrero State in the south, chose to attack now and whether it signaled the start of a long campaign remained a mystery, security analysts said.
More than a dozen smaller rebel groups united to form the Popular Revolutionary Army in 1996. They announced themselves to the world at Aguas Blancas in Guerrero State, a spot where the police killed 17 people the year before in a crackdown on a movement for the rights of poor farmers.
Espousing a Leninist view, the group called in its founding remarks for the "restitution of sovereignty by the people" and the punishment of those behind the "repression, corruption, misery and hunger" afflicting the poor.