Iran said it had launched a domestically made satellite into orbit for the first time on Tuesday.
Iranian state television showed footage of a rocket blasting off from a launchpad and lighting up the night sky as it streaked into space.
The launch of the Omid (Hope) research and telecom satellite was hailed by Iran as a major step in its space technology timed to coincide with the 30th anniversary of the 1979 Islamic revolution that ousted the US-backed shah.
The long-range ballistic technology used to put satellites into orbit can also be used for launching warheads, although Iran says it has no plans to do so.
"Dear Iranian nation, your children have placed the first indigenous satellite into orbit," President Mahmoud Ahmadinejad said in a televised message, adding the launch was successful.
Defence Minister Mostafa Mohammad Najjar said Omid was orbiting earth. The ISNA news agency quoted him as saying: "We have established communications with it and the necessary information has been received."
Senior officials from six world powers - the United States, Russia, Britain, France, Germany and China - meet on Wednesday to discuss the nuclear row with Iran. It will be their first meeting since US President Barack Obama took office.
President Obama has signalled that he will pursue direct talks with Tehran but has also warned Iran to expect more pressure if it does not meet the UN Security Council demand to halt atomic work the West fears has military aims.