At least 20 people drowned after a boat capsized off the coastal town of Tanur in India's southern state of Kerala, local authorities said on Monday.

The death toll was likely to rise as the boat was stuck in muddy waters and was being pulled out to rescue those trapped inside, Kerala's minister for fisheries and harbour development, V. Abdurahiman told reporters. He said 12 bodies had been identified so far.

The incident in the Malappuram district of the state took place at around 7 p.m. local time and a team from the National Disaster Response Force was at the site, a Kerala State Disaster Management Authority (KSDMA) spokesperson told Reuters.

"Pained by the loss of lives due to the boat mishap in Malappuram, Kerala," Indian Prime Minister Narendra Modi said in a tweet.

($1 = 81.7200 Indian rupees) (Reporting by Mrinmay Deya and Jyoti Narayan in Bengaluru, and Jose Devasia; Editing by Sandra Maler and Deepa Babington)