Iran's president has said that the Islamic Republic will soon announce "very important" achievements in the nuclear field, during an address to crowds celebrating the anniversary of the country's 1979 revolution.
Ahmadinejad addressed tens of thousands of supporters in Tehran's Azadi [Freedom] Square on Saturday as Iranians across the country joined state-organised rallies to mark the occasion.
"In the coming days the world will witness Iran's announcement of its very important and very major nuclear achievements," Ahmadinejad told the crowd in a speech relayed live on state television. He gave no further details.
The president spoke from a stage in front of which a full-scale model of a captured US spy drone was erected, which Iranian officials said they brought down by hacking its flight controls as it overflew their territory in December on a surveillance mission.
Demonstrators carrying Iranian flags and pictures of Supreme Leader Ayatollah Ali Khamenei chanted slogans against Israel and the US.
The overthrow of the US-backed Shah Mohammad Reza Pahlavi on February 11, 1979 was soon followed by a referendum that established the Islamic Republic, with Ayatollah Ruhollah Khomeini, the leader of the revolution, as its supreme leader.
Ismail Haniyeh, the Hamas prime minister in Gaza, gave a speech at Ahmadinejad's side vowing that his Islamist movement would continue its "resistance" to Israel.
"They want us to recognise the Israeli occupation and cease resistance but, as the representative of the Palestinan people and in the name of all the world's freedom seekers, I am announcing from Azadi Square in Tehran that we will never recognise Israel," Haniyeh told the crowd.
"The resistance will continue until all Palestinian land, including Al-Quds [in Jerusalem], has been liberated and all the refugees have returned."
The model drone and appearance by Haniyeh come as Iran confronts US-led Western economic sanctions and Israeli threats of military action against its nuclear programme.
Supreme leader Ayatollah Ali Khamenei, Ahmadinejad and other Iranian officials have said they will not abandon their "rights" to a nuclear programme, which they maintain are exclusively non-military in nature.
The US, Israel and other Western nations say Iran is seeking to build an atomic bomb.
Washington and the European Union have ratcheted up economic sanctions on Iran to an unprecedented level to try to force it to halt uranium enrichment and re-engage in long-stalled talks.