Washington: The United States continues to press Pakistan to tighten nuclear export controls to prevent any future black market proliferation, Assistant Secretary of State Christina Rocca has said.

She noted that though Islamabad is supporting Washington's efforts against international terror network al Qaeda, its record on domestic terror is "more complicated".

She said Pakistan's nuclear programme still remained under scrutiny after it was linked to a non-proliferation network led by disgraced Pakistani scientist and father of nuclear bomb Abdul Qadeer Khan, adding Washington continued to ask Islamabad for information on the network and investigation was on.

"It continues and we're working very closely with the Government of Pakistan on the investigation," she said in response to a question by democratic representative from New York Gary Ackerman at the House Subcommittee hearing on International Relations yesterday (June 22, 2004).

US Opposition Democratic legislators have demanded that the Government tie aid to Pakistan with progress it makes on non-proliferation and democratisation.

She said Pakistan has recently introduced a bill in Parliament which, if passed "would go a long way towards meeting the standards that we are encouraging them to reach."

Pakistan gives US excellent support against al Qaeda and Taliban but its record on domestic terror is "more complicated", Rocca told the committee chaired by James Leach.