TEHRAN, Iran — A former senior Iranian nuclear negotiator has been charged with passing classified information to foreigners, including the British Embassy, the Iranian intelligence minister said Wednesday, according to the official IRNA news agency.

Hossein Mousavian, who was a deputy of the top negotiator under reformist former President Mohammad Khatami, was briefly detained in May, again on suspicion of espionage, according to the semiofficial Fars news agency.

"His crime from the viewpoint of the Intelligence Ministry is obvious and provable," IRNA quoted Intelligence Minister Gholam Hossein Mohseni Ejehi as saying.

There was no word on when his trial would begin.

"From the viewpoint of the Intelligence Ministry, he is a criminal. ... This is definite and provable. But the decision (on the case) rests with the judge," Ejehi said, according to Fars.

Iran's refusal to suspend uranium enrichment has been the main trigger for existing U.N. sanctions and the threat of new ones. Iran, which says it has a right to enrich to generate power, has repeatedly said it will not mothball its program.

On Monday, hard-line President Mahmoud Ahmadinejad blasted critics of his nuclear policies as "traitors" and accused them of spying for Iran's enemies, using his strongest rhetoric yet against domestic opponents and raising concerns of a possible crackdown.

"We even have a recorded speech of one of them telling the enemy, 'Why should you give up? ... Step up pressures to make them (Iran) retreat,"' Ahmadinejad said, without identifying the person at the time.

He warned that his government would not let political groups use their "political and economic influence to save criminals from the clutches of justice."

Ejehi, himself a former top judge, named Mousavian directly, saying "influential persons have called the judge and tried to get him (Mousavian) acquitted."

Mousavian appeared Monday next to his ally, powerful former President Hashemi Rafsanjani, when he warned that Iran was facing "serious threats." It was Mousavian's first major public appearance since being released in May.

When he came to power in 2005, Ahmadinejad removed Khatami's negotiating team, which he had accused of making too many concessions to the West. He installed his own team, led by Ali Larijani and has since taken a tough line, refusing to bend to U.N. demands that Iran suspend its uranium enrichment program.

Larijani's predecessor, Hasan Rowhani, delivered an unusually sharp rebuke to Ahmadinejad last month, saying he was making more enemies for Iran with his policies.

Larijani had built a good working relationship with the U.N. and developed a style at odds with the president's more confrontational approach. He abruptly resigned in October.

Ahmadinejad replaced Larijani with a close loyalist, Saeed Jalili — a step that angered even some conservative politicians.

The president has long faced domestic criticism that he was failing to improve the worsening economy. Criticism of Ahmadinejad from within Iran has lately mounted over the nuclear issue, with Rowhani delivering an unusually sharp rebuke to Ahmadinejad last month. He and other critics say the president is making more enemies for Iran with his policies and inflammatory speeches.