Ahmad Tavakoli, a leading MP who heads the research centre, told the Fars news agency that the unidentified individual had been "arrested with the cooperation of the intelligence ministry".

The accused had worked since 2001 at the research centre, which provides background information to help draft legislation, he said.

"During this time he was collecting information and transferring it to the Monafeghin (hypocrites)", he said, using the authorities' customary shorthand for the banned People's Mujahedeen opposition group.

Tavakoli did not give further details or say when the individual was arrested but state radio said he had been giving "nuclear information to the Monafeghin".

"The accused's case has been completed for trial and soon the trial will start," Tavakoli added.

Amid increasing tensions over Iran's controversial nuclear programme, the authorities have arrested several "spies" in recent years. The People's Mujahedeen in 2003 revealed the existence of sensitive Iranian nuclear sites that had hitherto been kept secret.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.