JAKARTA: Days of severe flooding in parts of Indonesia, Thailand and Malaysia have killed more than 300 people, authorities said on Friday, as rescue and relief efforts continued in the worst-affected areas in the region.

Heavy monsoon rains, exacerbated by a tropical storm, caused flash floods and triggered landslides that have inundated areas throughout the three countries, leaving residents stranded on rooftops and cut off from electricity and communication lines.

In Indonesia, the death toll climbed to 174 on Friday, as flooding and landslides hit three provinces on Sumatra island — North Sumatra, West Sumatra and Aceh.

“North Sumatra is the hardest-hit … There are still areas that we can’t access and we’re still working on clearing the area. On the sites where landslides occurred that we cannot access yet, there are indications that there may be more victims,” Suharyanto, who heads Indonesia’s National Disaster Mitigation Agency, or BNPB, said at a press conference.

Indonesian authorities were still struggling to reach some of the hardest-hit areas.

Three planes have been dispatched for cloud seeding in the three provinces to try to prevent more rain and move along the rescue and relief efforts, while aid and rescue personnel have been airlifted into areas that are still inaccessible, Suharyanto said.

On social media, footage and photos from the past week show the collapse of houses and bridges in parts of Sumatra, caused by the overflow of rapid currents of water.

Thailand was also hit by some of the region’s worst flooding in recent years this past week, after the hardest-hit southern city of Hat Yai recorded 335mm of rain in a single day on Nov. 21 — the city’s highest in a single day for 300 years.

At least 145 people have been killed across southern Thailand as of Friday, government spokesman Siripong Angkasakulkiat said, as receding floodwater revealed a clearer picture of the disaster that submerged communities for days and left residents clinging to rooftops awaiting rescue by boat.

Most of the deaths were recorded in Songkhla province, where hospitals are reportedly out of room to receive bodies and are relying on refrigerated trucks.

In neighboring Malaysia, meteorological authorities warned of more heavy rain and winds on Friday, after tropical storm Senyar made landfall at about midnight and has since weakened.

Malaysia’s National Disaster Management Agency reported two deaths from flooding, which also forced the evacuation of about 30,000 people in nine states this week, including four that border Thailand.

Across the Indian Ocean, heavy downpours flooded parts of Sri Lanka and triggered landslides. Government offices and schools in the island nation were closed on Friday, as the death toll rose to 56.