The Toba Kakar Mountains (Urdu: توبہ کاکڑ) are a southern offshoot of the Himalayas in the Balochistan region of Pakistan. The historical route through the mountains is known as the Bolan Pass. The mountains originally received media attention in August 1979; when evidence emerged that Pakistan may be using them as a potential workspace towards development of nuclear weapons. Again in April 1981, the United States government raised concerns, this time with Senator Alan Cranston referring specifically to a nuclear test site, built into the side of the mountains, 40 kilometres from Afghanistan.