Iran says it has successfully tested and produced fuel rods for use in nuclear power plants. It also says it has test-fired a medium-range surface-to-air missile near the strategic Strait of Hormuz.
Iranian television said the rods, which contain natural uranium, were made in Iran and inserted into the core of a research nuclear reactor in Tehran.
The Tehran Times newspaper called the fuel rod production a "great achievement [that] will perplex the West."
State media also boasted that the missile tested Sunday was equipped with technology enabling it to pinpoint radar-evading targets.
At the same time, Iranian officials were dismissing Washington's move to impose new sanctions on financial institutions that deal with Iran's central bank. U.S. President Barack Obama signed the sanctions into law Saturday as part of a push to hamper Tehran's ability to finance its nuclear enrichment program.
Both the United States and the European Union contend that Iran is secretly trying to develop nuclear weapons. Iran says its nuclear intentions are peaceful.
Iran has threatened to respond to possible wider sanctions on its oil exports by closing the Strait of Hormuz, a vital export route for the other oil-producing countries of the Persian Gulf. The U.S. Navy's Fifth Fleet, based in Bahrain, says it will not allow disruptions to Gulf shipping.
There has been no official response in Western capitals to the latest Iranian announcements, which came a day after Tehran proposed a new round of talks with the West on its nuclear activities.
The state-run news agency IRNA quoted national security adviser Saeed Jalili as saying he was inviting the five permanent members of the U.N. Security Council and Germany - known as the P5+1 - to "come back to talks." The agency said Iran's ambassador to Germany would present the proposal to the European Union's foreign policy chief, Catherine Ashton.
The P5+1 last met with Iran nearly a year ago, but the talks ended with no agreement. At the time, Jalili said Tehran would maintain its right to nuclear technology, including uranium enrichment.
Some information for this report was provided by AP and AFP.