(CNN) -- The death toll from a tropical storm in the southern Philippines has reached more than 900, an official with the country's disaster agency said Monday.
Benito Ramos of the National Disaster Risk Reduction and Management Council said the toll stood at 927.
The Philippines Red Cross reported a lower death toll, at 713.
Tropical Storm Washi affected more than 167,000 people, the council said in a report Monday. About 88,000 people were being served at evacuation centers.
President Beningo Aquino plans to visit the region Tuesday.
U.S. President Barack Obama issued a statement Monday expressing "deep condolences for the tremendous loss of life and devastation."
He said the United States "stands ready to assist the Philippine people and government should humanitarian assistance and recovery efforts be needed."
The Red Cross noted that hundreds are missing after entire villages were swept away. The stench of death permeated the air as aid workers scrambled to help survivors.
Military and disaster officials said the vast majority of the dead were found in the port cities of Iligan and Cagayan de Oro, many of them swept away as they were sleeping. Water-logged bodies from washed-away villages floated at the shoreline on the northwestern coast of Mindanao island.
Five people were killed in a landslide, but virtually all the others died in flash flooding after Tropical Storm Washi, which is called Sendong locally.
Survivors in the hardest-hit areas are contending with no electricity or clean drinking water. One woman in Cagayan de Oro collected murky brown floodwater in a bucket, just meters away from where a destroyed vehicle was submerged.
Flash flooding overnight Friday, following 10 hours of rain, fueled the devastation. As much as 20 centimeters (8 inches) of rain fell within 24 hours in some areas. December generally brings about 60 millimeters of rain (a little over 2 inches) to the region, CNN Meteorologist Pedram Javaheri reported.