WASHINGTON, Nov 19: The United States and the European Union should use their influence on Pakistan to allow international nuclear experts to interview Dr A. Q. Khan, US nuclear experts told a congressional briefing in Washington.

David Albright, a physicist and former arms inspector, and Kenneth Pollack, former CIA analyst, told US lawmakers on Thursday that the International Atomic Energy Agency (IAEA) would never learn how close Iran was to making nuclear weapons without interviewing Dr Khan.

The briefing on Iran's nuclear program was attended by lawmakers from both Republican and Democratic parties, besides senior officials, academics, journalists, diplomats and lobbyists.

Mr Albright, who now heads a Washington-based anti-nuclear group, told the gathering it was unfair to criticize the IAEA for failing to make a complete assessment of Iran's nuclear program.

Such an assessment, he said, could not be made without interviewing Dr Khan, the man who founded Pakistan's nuclear program and, according to Mr Albright, also enabled Iran to fulfil its nuclear ambitions.

The Vienna-based UN nuclear agency, he said, "still has one major job ahead of it, to interview Pakistani nuclear scientist A. Q. Khan" about possible transfers of nuclear material to Iran.

"It may be unachievable, but it is very important that the US put pressure on Pakistan to allow this, because you cannot trust the Pakistani government in the end to represent what A. Q. Khan says," said Mr Albright.