may be one of the most powerful storms to ever hit the country. The president called for prayers, and hospitals and troops prepared for the worst.

With winds gusting up to 143 mph, Cimaron, named after a Philippine wild ox , roared across an impoverished mountainous area home to some 1.7 million people.

"This is probably one of the strongest typhoons ever to hit the country," Health Secretary Francisco Duqueso said at a news conference aired on Manila radio stations. "We need to be very careful and we need to instruct our people to make sure that all necessary precautions are being taken."

President Gloria Macapagal Arroyo ordered schools and government offices closed in the affected area and suspended bus services in the region.

"Let us pray," she said in a national radio address.

Although the storm did not appear to be drenching the mudslide-prone area as badly as feared, rising rivers made some bridges impassable. Officials said water would be released from two major dams to prevent them from overflowing.

Hours before Cimaron made landfall, Isabela province was placed under the highest of a four-step warning system to advise residents to abandon vulnerable coasts and mountains.

"The wind is really blowing strong. Trees are swaying and I can hear tin roof sheets banging about. Large areas are without light. We're expecting the worst," Armand Araneta, a provincial Office of Civil Defense officer, told The Associated Press by phone from Isabela.

Arroyo, who is visiting China, urged authorities and residents in four northern provinces to brace for the worst from the 16th typhoon to hit the country this year.

"I appeal to you not to venture out," Arroyo said in her radio address.

The typhoon threatened commemorations for All Saints' Day on Wednesday, a public holiday when millions travel to cemeteries to remember their dead, some leaving days in advance for outlying provinces. Officials warned people to cancel trips to threatened areas.

"We know in our culture that we should visit our dead, but this is not an ordinary typhoon, it's a super typhoon," a government official, Graciano Yumul, warned.

Forecasters said the storm was expected to weaken while traveling over land, but still should maintain typhoon strength as it emerges into the South China Sea.

The last time a typhoon this strong struck the Philippines was in December 2004, although in that case, the storm was deflected by a mountain range and casualties were minimal.

Last month, Typhoon Xangsane left 230 people dead and missing as it ripped through Manila and neighboring provinces.

About 20 typhoon and tropical storms lash the country each year.

Associated Press writer Jim Gomez contributed to this report.