The Obama administration has said that it is in constant touch with the Pakistani government in regard to disgraced Pakistani nuclear scientist A Q Khan who, it said, remained a nuclear non-proliferation concern.
"We have said consistently that we have real concerns about Mr A Q Khan. We believe that he remains a risk for proliferation," the State Department spokesman, Ian Kelly, told media-persons on Tuesday at his daily press briefing.
However, he refrained from making any comment on Khan's latest revelation that Pakistan had supplied nuclear know-how to countries such as China, Iran, Libya and North Korea.
Britain's Sunday Times, quoting a four-page 'secret' letter from Khan addressed to his Dutch wife Henny, had said that Pakistan had shared nuclear technology with these countries.As Khan remains a real concern for the US, Kelly said, "For that reason, we stay in very close contact with the Pakistani authorities to ensure that there is no proliferation risk from him or from any other source in Pakistan."