MEXICO CITY (AP) - Mexico's government said Tuesday that a series of gas pipeline explosions were attacks aimed at weakening the nation's democratic institutions after a small, leftist rebel group claimed responsibility.
The Interior Department said it was stepping up security at "strategic installations" across Mexico after an explosion Tuesday at a pipeline run by the state-owned Petroleos Mexicanos, or Pemex, and two other blasts that rocked gas ducts on Thursday. No one was injured in the blasts.
"The Mexican government categorically condemns the attacks against Pemex facilities. This criminal conduct aims to weaken democratic institutions, the patrimony of Mexicans and the safety of their families," the statement said.
While officials said investigations were continuing into the cause of the blasts, the statement by the Interior Department _ responsible for domestic security _ came a short time after a small guerrilla group said its members had planted explosives on the pipelines.
While the Interior Department statement did not specifically confirm the group's responsibility, it appeared to rule out any accidental cause.
The rebel statement said "three combined squads of urban and rural units ... have carried out surgical harassment actions by placing eight explosive packs on the Pemex pipelines." Posted on a Web site that serves as a clearinghouse for bulletins from armed groups, the statement demanded the release of two men detained in southern Oaxaca state in May, and others it identified as "political prisoners."
The city was seized by leftist groups for five months in 2006 before federal police broke up barricades and protest camps in October and arrested dozens.
While guerrilla groups in Colombia have regularly attacked energy facilities, the tactic hasn't been used much in Mexico until now.
It was impossible to independently confirm the claim, made by the "military zone command of the People's Revolutionary Army," or EPR, a tiny group that has largely been inactive in recent years. However, a breakaway faction of the same group had issued similar demands in a communique sent to The Associated Press in June.
Tuesday's explosion forced the evacuation of communities around the town of Coroneo, near the central city of Queretaro, but caused no damage outside of the pipeline's installations, Pemex said in statement.
Service was suspended on the 36-inch pipeline that runs between Mexico City and Guadalajara. The company didn't say when it would be restored.
On July 5, two explosions at another Pemex pipeline in the nearby Guanajuato state forced evacuations but caused no injuries.
That blast forced the temporary suspension of work at a Honda car plant in the city of Guadalajara, the government news agency Notimex reported Tuesday.
The EPR staged several armed attacks in southern Mexico in the 1990s. Tuesday's statement was signed both by the EPR and a splinter group known as the People's Democratic Revolutionary Party.