Sunday clawing through mud and debris searching for bodies as well as survivors of the accident in the remote village in Chandel district bordering Myanmar.
“So far we have reports of 20 people killed when a hillock caved and trapped the villagers,” magistrate Memi Mary told AFP by telephone from Chandel town.
Torrential rain has triggered flooding elsewhere in India including in the worst-hit western state of Gujarat where the death toll has hit 53.
In West Bengal some 42 people have been killed in the last week from flooding, while some 250,000 homes have been destroyed, state disaster management minister Javed Ahmad Khan said.
Rescuers in Vietnam were battling toxic mudslides from flood-hit coal mines in the northern province of Quang Ninh, home to the Unesco-listed Halong Bay tourist site.
Seventeen people have been killed in recent flooding, including two families swallowed up by the toxic mud.
“In one second, mud and rock smashed into my house. We were lucky to escape with our daughter,” To Thi Huyen, a 37-year-old primary school teacher, told AFP.
Inundations have also hit Pakistan with 109 killed and almost 700,000 affected by floods in the last two weeks, while 36 people have perished in landslides in Nepal.
Two of the worst-hit areas in Myanmar are the remote and impoverished western states of Chin and Rakhine.
The Myanmar Red Cross Society said 300 homes in Rakhine had been destroyed or damaged, with around 1,500 people evacuated to shelters.
“The figures are expected to increase in the coming days as Red Cross assessment teams access remote areas of Rakhine affected by the flooding,” the agency’s head Maung Maung Khin said in a statement released on Sunday.
Rakhine already hosts some 140,000 displaced people, mainly Rohingya Muslims, who live in exposed makeshift coastal camps following deadly 2012 unrest between the minority group and Buddhists.
Rescue workers have been mobilised across the country but the sheer extent of the flooding is testing the government’s limited relief operations, officials admit.
In Bago region, three hours north of Myanmar’s commercial hub Yangon, floodwaters had forced more than a thousand to take shelter in a monastery.
“There’s just too much rain this year and the dams had to let the water out,” construction worker Hla Wai, whose house was partially underwater, told AFP at the monastery.
Myanmar’s annual monsoon is a lifeline for farmers but the rains and frequent powerful cyclones can also prove deadly, with landslides and flash floods a common occurrence.