The death toll from landslides and floods triggered by days of heavy rains in the Philippines has risen to 13 after rescuers found more bodies, officials said Tuesday.

Civil defense administrator Benito Ramos said nearly 13,000 people have sought shelter in schools and gymnasiums turned into evacuation centers in 12 provinces on the country's eastern seaboard.

The dead include six children, three of them dug from a wall of mud that buried their homes Sunday as they slept in the central Philippines' St. Bernard township. The town in Southern Leyte province had one of the country's worst disasters in 2006 when a mudslide buried the entire village of Guinsaugon, with more than 1,000 people killed.

President Benigno Aquino III ordered an investigation into why deaths again occurred in St. Bernard, a town known prone to landslides. He also ordered the quick evacuation of residents in areas susceptible to landslides and flood "to reduce the risk that these communities are facing."

Ramos said of the 13 dead, eight died of drowning while the rest were killed in landslides. One person missing in Southern Leyte, he added.

The latest fatalities include two men buried by a landslide in southern Butuan city and another man who drowned in southern Surigao del Norte province.