Atal Bihari Vajpayee, who as India’s prime minister from 1998 to 2004 stunned the world by ending a decades-old moratorium on nuclear weapons tests but nevertheless managed to ease tensions with Pakistan and build closer ties to the United States, died on Thursday in New Delhi. He was 93.

The Indian central government announced his death but gave no further details. The Times of India said that Mr. Vajpayee, a diabetic, was admitted to the All India Institute of Medical Sciences in New Delhi on June 11 with kidney tract infection and other ailments, and had recently been placed on life support.

A published poet, Mr. Vajpayee dabbled in law, journalism and rebellion against British colonialism as a young man. A leader of the Hindu nationalist opposition to the once-invincible Indian National Congress party of Gandhi and Nehru, he was virtually unknown outside India for most of his 50 years in politics.

But for six years in his late 70s, Mr. Vajpayee was the face of the world’s most populous democracy, a nation of one billion whose ethnic, religious and regional conflicts had fomented massacres, three wars with Pakistan and internal strife for a half-century after independence from Britain in 1947.