New Delhi, March 17 -- Two boats carrying 21 people capsized Monday off Henoko, a controversial relocation site for a U.S. military base off Japan's southern island of Okinawa, throwing all into the water and leaving two of them dead, officials said.

The Japan Coast Guard said 18 of them were students from a Kyoto high school on two boats, 10 on Heiwa Maru and eight on the smaller Fukutsu, to observe the Henoko area as part of their peace education program.

Coast guard rescuers pulled all 21 people out of the water, but a 17-year-old female student and the captain of Fukutsu were later pronounced dead, officials said. Two people were injured but their conditions are not life threatening.

Coast guard officials said the cause of the acci...