Four people died in floods in northeast India following heavy rains in the state of Assam, local authorities reported on Wednesday.

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Since mid-May, 38 people have died due to heavy rains that have lashed the state, causing floods and landslides, according to local disaster authorities.

During the monsoon season, floods and landslides are common and cause major damage in India. However, due to climate change, monsoon rains are becoming heavier and more frequent, scientists say.

The India Meteorological Department has issued warnings for several states, including Assam, warning of the risk of further flash floods.

In the state of Assam, floods damaged roads and 13 fishermen, stranded on an island, were rescued by the air force.

Large parts of Kaziranga National Park, a UNESCO World Heritage Site and home to the world's largest rhino population, were also submerged in floodwaters.

“Forest guards have been alerted,” Arun Vignesh, a park official, told AFP. “Hundreds of animals have started crossing the highway in search of higher ground,” he said.

Floods also submerged parts of Bangladesh bordering northeastern India.

Monsoon rains account for about 80% of South Asia's annual rainfall. They are vital for river levels, water recharge and agriculture, but they are deadly every year.

In late June, at least 14 people died after monsoon rains hit Nepal, triggering landslides and flooding.

In Bangladesh, at least nine people died in landslides in June.

Six people have died in flash floods and landslides in Sikkim, an Indian state located in the foothills of the Himalayas on the border with China.