WASHINGTON, Jan 28: The White House on Wednesday downplayed concerns that Pakistani scientists sold nuclear secrets on the world black market, citing Islamabad's assurances that such activities were "part of the past."

President Pervez Musharraf "has assured us that that's, one, part of the past, and the past is the past," spokesman Scott McClellan told reporters.

President Musharraf has further told the United States that "the government of Pakistan is not involved" in any clandestine nuclear sales and has launched an investigation into the matter, said Mr McClellan.-AFP