Youths wade in a storm surge along Manila Bay amid heavy rains brought by Tropical Storm Yagi in Manila. AFP

A storm set off landslides and unleashed pounding rains that flooded many northern Philippine areas overnight into Monday, leaving at least 14 people dead and prompting authorities to suspend school classes and government work in the densely populated capital region.

Tropical Storm Yagi slammed into Casiguran town in the northeastern province of Aurora Monday afternoon and gained strength with sustained winds of 85 kilometresper hour and gusts of 105kph, according to the weather bureau.

The storm, locally called Enteng, gained speed and was moving northwestward at 20kph toward the country’s northernmost provinces. It was forecast to strengthen further, possibly becoming a typhoon, before blowing away toward southern China in the next two days, the weather bureau said.

At least 14 people died, mostly due to landslides and drownings, officials said.

A landslide hit two small shanties on a hillside in Antipolo city on Monday in Rizal province just to the west of the capital, killing at least three people, including a pregnant woman. Four other villagers drowned in swollen creeks, Antipolo's disaster-mitigation officer Enrilito Bernardo Jr. told The Associated Press by telephone.

"The creeks overflowed and a part of the hillside gave in because of the heavy rains,” Bernardo said.

Four residents died in separate landslides in central Cebu city and Northern Samar province. Three others died in the eastern city of Naga - two by drowning and one due to electrocution, officials said.

This photo shows the boats are seen shrouded by dark clouds amid heavy rains at Manila Bay on Monday. AFP

Storm warnings were raised in a large swath of Luzon, the country’s most populous region, including in metropolitan Manila, where schools at all levels and most government work were suspended due to the stormy weather.

Along the crowded banks of Marikina River in the eastern fringes of the capital, a siren was sounded in the morning to warn thousands of residents to brace for evacuation in case the river water continues to rise and overflows due to heavy rains.

In Northern Samar province, coast guard personnel used a rope to evacuate 40 villagers on Sunday in two villages that were engulfed in waist-high floods, the coast guard said.

Sea travel was temporarily halted in several ports affected by the storm, stranding about 2,400 ferry passengers and cargo workers, and nearly two dozen domestic flights were suspended due to the stormy weather.

People walk past a fallen electrical post brought down by strong winds in Manila on Monday. AFP

Downpours have also caused water to rise to near-spilling level in Ipo dam in Bulacan province, north of Manila, prompting authorities to schedule a release of a minimal amount of water later Monday that they say would not endanger villages downstream.

About 20 typhoons and storms batter the Philippines each year. The archipelago lies in the "Pacific Ring of Fire,” a region along most of the Pacific Ocean rim where many volcanic eruptions and earthquakes occur, making the Southeast Asian nation one of the world’s most disaster-prone.

In 2013, Typhoon Haiyan, one of the strongest recorded tropical cyclones in the world, left more than 7,300 people dead or missing, flattened entire villages, swept ships inland and displaced more than 5 million people in the central Philippines.

Associated Press