Iranian dissidents say that Tehran is still researching nuclear arms at facilities it relocated to escape detention.

The Mujahedin-e Khalk, or MEK, cites Iranian government sources it did not identify. It said Wednesday that Iran's Organization of Defensive Information and Research, or SPND, moved its most sensitive weapons research to a new Tehran location "in recent months."

It says Mohsem Fakhrizadeh, whom it described as a Revolutionary Guard brigadier general, leads the SPND.

Some — but not all — of the MEK's previous information has been confirmed by Western governments and the U.N. nuclear agency probing Tehran's atomic activities.

In announcing sanctions on SPND in August, the U.S. government described it as "primarily responsible for research in the field of nuclear weapons."

Iran denies working or seeking such arms.