In December 1971, during the Indo-Pakistani War, the U.S. government sent a carrier battle group led by the into the Bay of Bengal in an attempt to intimidate India. The Soviet Union responded by sending a submarine armed with nuclear missiles from Vladivostok to trail the US task force. The Soviet response demonstrated the deterrent value and significance of nuclear weapons and ballistic missile submarines to Indira Gandhi. India gained the military and political initiative over Pakistan after acceding to the treaty that divided Pakistan and led to the creation of Bangladesh.