DHAKA, Bangladesh — Authorities in Bangladesh and Myanmar prepared to evacuate hundreds of thousands of people Friday, warning them to stay away from coastal areas as a severe cyclone churned in the Bay of Bengal.

Cyclone Mocha is expected to hit land on Sunday with wind speeds of up to 160 kilometers (100 miles) per hour and gusts up to 175 kph (110 mph) between Cox’s Bazar in Bangladesh and Kyaukpyu in Myanmar, India's Meteorological Department said.

Bangladesh, a delta nation with more than 160 million people, is prone to natural disasters such as floods and cyclones. The evacuation of nearly 500,000 people is expected to start Saturday with 576 cyclone shelters ready to provide refuge to those who are moved from their homes along the coast, said Bangladesh government administrator Muhammad Shaheen Imran.

The International Rescue Committee said in a statement the cyclone posed a threat to Rohingya refugees who fled from neighboring Myanmar and are living in camps in Cox's Bazar in Bangladesh.

"Still reeling from a devastating fire in March that destroyed more than 2,600 shelters and critical infrastructure, over 850,000 refugees risk losing their homes and livelihoods," the statement said.

The committee said it was scaling up its emergency response by deploying mobile medical teams to offer services to vulnerable groups such as women, girls, the elderly and people with disabilities. The IRC is a global humanitarian aid, relief and development nongovernmental organization.

“This is the first cyclone system in the north Indian Ocean this year,” said Rajendra Kumar Jenamani, a senior scientist at the Indian Meteorological Department. “The cyclone is severe and will likely affect millions of fishers and coastal communities in Bangladesh and Myanmar."

In May 2008, Cyclone Nargis hit Myanmar with a storm surge that devastated populated areas around the Irrawaddy River delta. At least 138,000 people died and tens of thousands of homes and other buildings were washed away.

Myanmar authorities warned of possible flash floods and landslides in coastal areas as residents stocked up on essential supplies, said Hla Tun, a director at the Department of Meteorology and Hydrology.

Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology in Pune city, said cyclones in the Bay of Bengal are becoming more intense more quickly, in part because of climate change.

The state-run Global New Light of Myanmar newspaper reported that emergency response exercises were being conducted in various regions. It said thousands of people living along the western coast of Rakhine state where the storm is expected to pass are being evacuated.

In Bangladesh, control rooms in cyclone-prone areas were ready for emergency support. Three ports were put on alert, Imran said.

He said the government has allocated dry food, rice and cash and organized thousands of volunteers for relief work under the Bangladesh Red Crescent Society.

Cyclone Mocha is expected to hit coastal districts including Chattogram, Cox’s Bazar, Noakhali and Bhola in Bangladesh on Sunday.

India’s Meteorological Department said the storm was centered more than 1,000 kilometers (600 miles) southwest of Cox’s Bazar and 930 kilometers (580 miles) southwest of Sittwe in Myanmar on Friday and was moving northward at 9 kph (5 mph).

Fishermen and ships were advised not to venture into the southeastern Bay of Bengal and northern Andaman Sea, it said.

The department said it was expecting heavy to very heavy rainfall in Andaman and Nicobar Islands and parts of India's remote northeast.

Climate scientists say cyclones can now retain their energy for many days, such as Cyclone Amphan in eastern India in 2020, which continued to travel over land as a strong cyclone and caused extensive devastation. "As long as oceans are warm and winds are favorable, cyclones will retain their intensity for a longer period,” Koll said.

Cyclones are among the most devastating natural disasters in the world, especially if they affect densely populated coastal regions in South Asia. (AP)