Iranian authorities have arrested the country's former nuclear negotiator an ally of hard-line President Mahmoud Ahmadinejad's predecessor and rival on an unspecified security charge.
The president, meanwhile, insisted his country will not retreat "even an iota" from its nuclear rights.
The Iranian state-run news agency, citing an "unofficial informed source," announced Wednesday that Hossein Mousavian was arrested in the capital, Tehran, on Monday.
He was a member of the Iranian nuclear negotiating team until 2005 and served as Iran's ambassador to Germany in the late 1990s and early 2000s.
He was known as a close ally to influential former President Akbar Hashemi Rafsanjani. Ahmadinejad, who defeated Rafsanjani in the last presidential elections, replaced the entire Iranian negotiating team, including Mousavian, when he assumed power two years ago.
Rafsanjani, a high-ranking cleric, holds seats on two of Iran's most important government bodies and is considered Ahmadinejad's main political rival. Seen as a more pragmatic conservative than Ahmadinejad, Rafsanjani has taken a somewhat more conciliatory stance toward the U.S. and its allies over Tehran's nuclear program.
Iran did not release any details about the specific charges against Mousavian, but in such cases they usually involve violating national interests or state security interests or treason. These cases are heard before Iran's Revolutionary Courts and carry sentences up to life in prison.
Ahmadinejad who is locked in a bitter standoff with the West over its disputed nuclear program warned Wednesday that Iran would "cut off the hands of invaders" if attacked.
Speaking to a crowed in Kerman, about 1,050 kilometers (650 miles) southeast of Tehran, the hard-line president said Iran would continue to resist attempts to curtail development in nuclear technology for peaceful, electricity-generating purposes.
"Our nation will not give up its right even an iota," he said. "In the important nuclear issue, implementation of justice is the demand of Iranian nation. Our nation says, 'laws for everyone, rights for everyone."'
Ahmadinejad's comments came ahead of another U.N. Security Council deadline for Iran this one in late May to halt its uranium enrichment program or face more sanctions.
The Security Council first imposed limited economic sanctions on Iran in December, then strengthened them last month over Iran's continued refusal to suspend enrichment.
The enrichment process can produce fuel for nuclear reactors or if taken to a higher degree the material for atomic bombs. The U.S. and some of its allies claim Iran is secretly trying to develop nuclear weapons allegations Tehran denies.
Earlier in April, Ahmadinejad said additional U.N. sanctions would only prompt Iran to even further increase its nuclear development.
The U.N.'s latest sanctions ban Iranian arms exports and freeze the assets of 28 individuals and companies involved in Iran's nuclear or ballistic missile programs. Iran has rejected the sanctions and announced a partial suspension of cooperation with the U.N. nuclear watchdog, the International Atomic Energy Agency.
Tehran also in April said it had begun operating 3,000 centrifuges at its Natanz facility nearly 10 times the previously known number. The United States, Britain, France and others criticized the announcement, but experts expressed skepticism about whether Iran's claims were true.