An exiled Iranian opposition group has accused a well-known Pakistani scientist of giving Tehran weapons grade uranium in 2001.

Farid Soleiman, a spokesman for the group, National Council of Resistance of Iran, made the comment Wednesday to reporters in Vienna, the home of the International Atomic Energy Agency.

He said the enriched uranium in question was given to Iran by Abdul Qadeer Khan, who built Pakistan's nuclear bomb. Mr. Khan ran a global nuclear black market that supplied Libya, North Korea and Iran with nuclear technology until it was shut down this year.

The Iranian opposition group also said Iran has been conducting secret nuclear activities at sites unknown to international inspectors.

International Atomic Energy Agency officials and the government of Iran have yet to respond to the accusations.

Some information for this report provided by AFP and Reuters.