BANDA ACEH, Indonesia — Governments and aid groups in Indonesia and Sri Lanka worked to rush aid on Tuesday to hundreds of thousands stranded by deadly flooding that has killed over 1,300 people in four countries.

Days of heavy monsoon rains inundated vast areas, leaving thousands stranded and many clinging to rooftops and trees waiting for help. The flooding and landslides killed at least 1,306 people: 712 in Indonesia, 410 in Sri Lanka, 181 in Thailand and three in Malaysia, authorities said on Tuesday.

Climate change is producing more intense rainstorms because a warmer atmosphere holds more moisture, and warmer oceans can turbocharge storms.

The floodwaters have now largely receded, but the devastation means hundreds of thousands of people are now living in shelters and struggling to secure clean water and food.

In Indonesia's Aceh, one of the worst-affected regions, residents told AFP that survivors who could afford to were stockpiling supplies.

"Road access is mostly cut off in flood-affected areas," 29-year-old Erna Mardhiah said as she joined a long queue at a petrol station in Banda Aceh.

"People are worried about running out of fuel," she added from the line she had been in for two hours.

The pressure has caused prices to skyrocket. "Most things are already sky-high … chilies alone are up to 300,000 rupiah ($18) per kilo, so that's probably why people are panic-buying," she said.

On Monday, Indonesia's government said it was sending 34,000 metric tons of rice and 6.8 million liters of cooking oil to the three worst-affected provinces, Aceh, North Sumatra and West Sumatra.

Aid groups said they were working to ship supplies to affected areas, warning that local markets were running out of essential supplies and that prices had already tripled.

Across the border in Malaysia, two more people were killed.

A separate storm brought heavy rains across all of Sri Lanka, triggering flash floods and deadly landslides that killed at least 410 people.

Hundreds of people remain missing, and some of the worst-hit areas in the country's center are still difficult to reach.

President Anura Kumara Dissanayake has declared a state of emergency to deal with what he called the "most challenging natural disaster in our history".

Unlike his Indonesian counterpart, he has called for international aid.

Sri Lanka's air force, backed by counterparts from India and Pakistan, has been evacuating stranded residents and delivering food and other supplies. In the mountainous Welimada region, security forces on Monday recovered the bodies of 11 residents buried by mudslides, a local official said.

In southern Thailand, cleanup has begun on streets and in buildings after massive floods affected more than 1.5 million households and 3.9 million people. Authorities are working to restore infrastructure.

Agencies via Xinhua