At least 31 people have died and nine others are missing after flash floods and landslides set off by torrential rains swamped a southern Philippine province, officials have said.

At least 26 people have died in the neighbouring towns of Datu Odin Sinsuat and Datu Blah Sinsuat, while five others died in Upi town, all in Maguindanao province.

A rescue team was deployed to a tribal village at the foot of a mountain in Datu Odin Sinsuat to check on reports that floods and landslides also hit houses in the area, officials said, adding there were no immediate reports of casualties.

The unusually heavy rains that flooded several towns in Maguindanao and outlying provinces overnight in mountainous regions with marshy plains were caused by Tropical Storm Nalgae, which was expected to hit the country’s eastern coast from the Pacific Ocean on Saturday morning, according to forecasters.

Floodwaters rapidly rose in many low-lying villages, forcing some villagers to climb onto their roofs, where they were rescued by army troops, police and volunteers.

The floods started to recede when the rains eased Friday morning.

“In one area in Upi only the attic of a school can be seen above the floodwater,” one officer said, referring to a flood-engulfed town in Maguindanao.

The wide rain bands of Nalgae, the 16th storm to hit the Philippine archipelago this year, enabled it to dump rains in the country’s south although the storm was blowing farther north, government forecaster Sam Duran said.

About 20 typhoons and storms batter the Philippines each year.

It is located in the Pacific Ring of Fire, a region along most of the Pacific Ocean rim where many volcanic eruptions and earthquakes occur, making the south-east Asian archipelago one of the world’s most disaster-prone areas.