Electricity was cut to wide areas of the southern Philippines on Saturday after suspected Muslim rebels blew up the main power transmission line with crude bombs, army and power company officials said.
Three or four improvised explosive devices made from mortar rounds toppled the transmission line tower in Lanao del Norte province on the southern island of Mindanao before dawn, army spokeswoman Steffani Cacho told reporters.
Cacho said the blasts hit the steel tower and snapped the high-voltage cable supplying electricity to three provinces on the Zamboanga peninsula and most parts of Misamis Occidental and Lanao del Norte provinces.
"We suspect rogue members of the Moro Islamic Liberation Front (MILF) are behind the attack," Cacho said, adding troops were sent to the area to guard engineers and technicians working to restore power.
Engineer Avelino Dawis, manager of the state-owned National Transmission Corporation in Iligan City, said repair workers were immediately sent to the area, but there were delays because they asked the military to provide security.
"We're doing our best to restore power as soon as possible in key urban centres in the affected provinces, including the main southern port city of Zamboanga," Dawis said.
Arvee Villafuerte, a spokesman from the company in Manila, said it might take two to three days to fully restore power but an existing 100-MW power plant near Zamboanga City was tapped to augment electricity supplies.
The attack came a week before a consortium led by China's State Grid Corp takes over operations of the country's power grid after the government sold it for $3.95 billion (Dh14.5bn) in December 2007.
Last year, nearly 40 steel towers holding transmission lines were either destroyed or damaged by bomb attacks by Muslim rebels and groups demanding protection money.