Rescuers in Indonesia are searching for at least 400 people who have been reported missing, many believed to be buried under landslides, after cyclonic rains caused disastrous flooding nearly a week ago.

The death toll on the island of Sumatra has risen to more than 440, the government says.

Aid has been sent into affected areas by air and by sea, but some villages have yet to receive anything, and there are reports of people stealing food and water to survive.

Torrential rain and storms have devastated parts of Thailand, Malaysia, the Philippines and Sri Lanka, affectingmillions of people and leaving more than 900 dead across the region this month.

An exceptionally rare tropical storm, named Cyclone Senyar, caused catastrophic landslides and flooding in Indonesia, with homes swept away and thousands of buildings submerged.

People are missing in Aceh, North Sumatra and West Sumatra, the National Disaster Management Agency said.

"There are two cities that require full attention due to being isolated, namely Central Tapanuli and Sibolga," agency head Suharyanto was quoted as saying by AFP news agency. Ships were expected in Sibolga on Monday, he added.

Some foreign aid has arrived, with Malaysia sending medical supplies to Aceh, one of the worst-hit provinces.

In Sungai Nyalo village, about 100km (62 miles) from West Sumatra`s capital Padang, floodwaters had mostly receded on Sunday, leaving homes, vehicles and crops coated in thick grey mud, AFP reports.

The authorities had not yet begun clearing roads, residents said, and no outside assistance had arrived.

"Most villagers chose to stay; they didn`t want to leave their houses behind," Idris, 55, told the news agency.

Police spokesperson Ferry Walintukan said there were reports of people breaking into shops on Sumatra, and police had been sent in to restore order, the Associated Press news agency reported.

"The looting happened before logistical aid arrived," Mr Walintukan added. "Residents] didn`t know that aid would come and were worried they would starve."

In another development, tech billionaire Elon Musk said he would provide free Starlink services to support communications during the emergency.

There has been widespread devastation across the region.

At least 170 people died in floods in Thailand and there were several deaths reported in Malaysia.

In Sri Lanka, more than 330 people died from floods and mudslides as the country grappled with one of its worst weather disasters in years.

While the torrential rains have now subsided, low-lying areas of the capital, Colombo, are still flooded and many areas in the centre of the country remain cut off.

In the Philippines, tens of thousands of people joined protests against government corruption on Sunday, for the second time this month, following a series of disastrous floods which killed more than 200 people.

The government has acknowledged that substantial funds meant to finance flood control have been lost through corruption.

Public anger over the issue now threatens the administration of President Ferdinand "Bongbong" Marcos Jr.

There were two large protests in the capital Manila, one organised by the Roman Catholic Church and the other by unions, students and left-wing activists.

Their complaint is the same – that money designated by the central government for flood defences was diverted into the pockets of corrupt politicians, leaving many communities dangerously exposed to this year`s exceptionally heavy rainfall.

But determining who is responsible is proving harder. Marcos Jr has sacked several politicians and officials he blames for stealing flood funds.

However, one of those politicians, who is now in hiding, has accused the president himself of supervising the corruption - Marcos Jr has dismissed that as propaganda.

His own sister, Senator Imee Marcos, has now joined opposition to him, and Vice-President Sara Duterte, a bitter rival of the president, says she is ready to take over should he be forced to resign. However, she too faces different corruption allegations.

Much now depends on whether the protests continue in the coming weeks and whether any more of the president`s allies desert him.

He will be mindful that two of his predecessors, including his father, were ousted by popular protest movements stirred up by corruption.