MEXICO CITY, Sept. 11 (Xinhua) -- Mexican guerrilla group the People's Revolutionary Army (EPR) said in a Tuesday statement that it had attacked gas pipelines belonging to state energy company Petroleos Mexicanos (Pemex) with 12 charges.

    The EPR said it has placed charges in the town of La Antigua, Ursulo Galvan, Olmeaca, Mendoza and Cumbres de Maltrata, all in the eastern state of Veracruz; and in Cuapiaxtla, in the central state of Tlaxcala.

    It said that one of the charges placed in La Antigua on the Nuevo Tepa-Caderyta 24-inch oil pipeline had not exploded. All the others had been detonated at 2:00 a.m. on Monday morning.

    The EPR said that the attacks are part of a campaign to free activists Edmundo Reyes Maya and Gabriel Alberto Cruz Sanchez, who guerrillas described as "disappeared-detained" since May 25 at the orders of soldiers in the southern state of Oaxaca.

    The EPR added that it will continue until its members are released alive and well.

    The guerillas had previously attacked Pemex facilities in July in the central states of Queretaro and Guanajuato. They have also attacked a jail construction site in the southern state of Chiapas and a mall in Oaxaca state.