Fifteen tons of heavy water that could be used to make nuclear weapons were illegally diverted to India, authorities said Friday. They fear India may have used the material in a secret weapons program.

India did not sign the 1968 Nuclear Non-Proliferation Treaty and is known to have tested nuclear devices. The Indian government, however, has denied that it operates a nuclear arms program.Tor Axel Busch, Norway's deputy public director of prosecutions, Friday confirmed reports that heavy water was flown from Norway to Basel, Switzerland, where it was rerouted via Dubai to Bombay, India. The reports were published last summer in the Oslo newspaper Verdens Gang.