A boat has capsized in southern India, killing at least 21 people, authorities have said.

The vessel, which was carrying about 40 passengers, overturned near the town of Tanur in the Malappuram district of Kerala state.

Police think it was overcrowded when it got into trouble at around 7pm local time on Sunday.

About 10 passengers were being treated in several hospitals.

Officials said they feared that some people might be still missing.

Kerala’s minister for fisheries and harbour development V Abdurahiman told reporters that the boat was stuck in muddy waters and attempts were being made to pull it out.

A team from the National Disaster Response Force was at the site, a Kerala State Disaster Management Authority spokesperson said.

Prime Minister Narendra Modi tweeted: “Pained by the loss of lives due to the boat mishap in Malappuram, Kerala.”