Tourist boat sinks off India, 21 killed

At least 21 people are feared dead after a boat capsized off the Andaman and Nicobar islands.

A boat carrying local tourists has capsized in India's Andaman Sea, killing 21 people. (AAP)

A boat carrying local tourists has capsized in India's Andaman Sea in the Bay of Bengal, killing 21 people, officials say.

Thirteen were rescued, said top Administrator P. Jawahar.

Rescuers were looking for another nine people believed to be missing, CNN-IBN television news channel reported.

The boat sank off the eastern Andaman and Nicobar Islands, and initial reports said the tourists were all Indians.

Jawahar said authorities were investigating the cause of the sinking.