Iran's President Mahmoud Ahmadinejad speaks at a ceremony marking the 33rd anniversary of the Islamic Revolution, in Tehran's Azadi square on Saturday, stating Iran would not discuss its nuclear program with the UN as long as 'enemies behave arrogantly.' (Raheb Homavandi/Reuters)

Iran will soon unveil "big new" nuclear achievements, President Mahmoud Ahmadinejad has vowed while reiterating Tehran's readiness to revive talks with the West over the country's controversial nuclear program.

Ahmadinejad spoke at a rally Saturday in Tehran as tens of thousands of Iranians marked the 33rd anniversary of the Islamic Revolution that toppled the pro-Western monarchy and brought Islamic clerics to power.

Ahmadinejad did not elaborate on the upcoming announcement but insisted Iran would never give up its uranium enrichment, a process that makes material for reactors as well as weapons.

The West suspects Iran's nuclear program is aimed at producing atomic weapons, a charge Tehran denies, insisting it's geared for peaceful purposes only, such as energy production.

Four rounds of UN sanctions and recent tough financial penalties by the U.S. and the European Union have failed to get Iran to halt aspects of its atomic work that could provide a possible pathway to weapons production.

"Within the next few days the world will witness the inauguration of several big new achievements in the nuclear field," Ahmadinejad told the crowd in Tehran's famous Azadi (Freedom) square.

Iran has said it is forced to manufacture nuclear fuel rods, which provide fuel for reactors, on its own since international sanctions ban it from buying them on foreign markets. In January, Iran said it had produced its first such fuel rod.

Apart from progress on the rods, the upcoming announcement could pertain to Iran's underground enrichment facility at Fordo or upgraded centrifuges, which are expected to be installed at the facility in the central town of Natanz. Iran has also said it would inaugurate the Russian-built nuclear power plant in the southern port of Bushehr in 2012.

Ability to sell oil limited

Iran's unchecked pursuit of the nuclear program scuttled negotiations a year ago but Iranian officials last month proposed a return to the talks with the five permanent UN Security Council members plus Germany.

"Iran is ready for talks within the framework of equality and justice," Ahmadinejad repeated on Saturday, but warned that Tehran "will never enter talks if enemies behave arrogantly."

In the past, Iran has angered Western officials by appearing to buy time through opening talks and weighing proposals even while pressing ahead with the nuclear program.

Washington recently levied new penalties aimed at limiting Iran's ability to sell oil, which accounts for 80 per cent of its foreign revenue, while the European Union adopted its own toughest measures yet on Iran, including an oil embargo and freeze of the country's central bank assets.

Israel is worried Iran could be on the brink of an atomic bomb and many Israeli officials believe sanctions only give Tehran time to move its nuclear program underground, out of reach of Israeli military strikes. The U.S. and its allies argue that Israel should hold off on any military strike on Iranian nuclear facilities to allow more time for sanctions to work.

Before Ahmadinejad spoke Saturday, visiting Hamas prime minister from Gaza, Ismail Haniyeh, also addressed the crowd, congratulating Iranians on the 1979 anniversary and vowing that his militant Palestinian group would never recognize Iran's and Hamas' archenemy, Israel.

Also at the Tehran rally, Iran displayed a real-size model of the U.S. drone RQ-170 Sentinel, captured by Iran in December near the border with Afghanistan. Iran has touted the drone's capture as one of its successes against the West.

The state TV called the drone is a "symbol of power" of the Iranian armed forces "against the global arrogance" of the U.S.

The report broadcast footage of other rallies around Iran, saying millions participated in the anniversary celebrations, many under heavy snowfall.