Iran's Islamic regime is celebrating 31 years in power by cracking down on political opponents and producing uranium enriched to a higher level.

At an anniversary rally on Thursday, President Mahmoud Ahmadinejad told the crowd that Iran has produced its first batch of highly enriched uranium.

"I want to announce with a loud voice here that the first package of 20 percent fuel was produced and provided to the scientists," he said. "We have the capability to enrich uranium more than 20 percent or 80 percent but we don't enrich (to this level) because we don't need it," the Iranian president said in a speech broadcast live on state television.

However, he insisted that Iran has no plan to build a nuclear weapon.

"When we say we do not manufacture the bomb, we mean it, and we do not believe in manufacturing a bomb," Ahmadinejad told the crowd. "If we wanted to manufacture a bomb, we would announce it."

The regime has arrested a number of opposition leaders and promised to forcefully put down street protests. There are reports of anti-government rallies in Tehran and other cities.

Meanwhile, security forces detained the granddaughter of Ayatollah Ruhollah Khomeini, who was the late leader of the Iranian Revolution in 1979, and her husband. Khomeini's granddaughter is a leader in the reform movement.