District Magistrate Vinod Sachan says the boat had been drifting on Monday after its engine malfunctioned and hit the post of a bridge, causing it to capsize.

Sachan did not know exactly how many people were aboard the boat, which was heading to a nearby boat race, but said some managed to swim to shore.

Emergency workers were on their way to the site of the accident on the Kolohi River, a tributary of the Brahmaputra River in the northeastern state of Assam.