Brazil’s president is in Iran to hold talks with its leaders in what is seen as a last ditch attempt to find a compromise over the nuclear issue.
Luiz Inacio Lula da Silva arrived from Moscow, where he met Russian President Dmitry Medvedev.
US officials have warned they are close to securing agreement on a new package of sanctions against Iran in the UN security council.
Iran insists its nuclear programme is for peaceful purposes.
Diplomatic effort
President Lula’s visit to Tehran has been described by both senior American and Russian officials as the last chance for a compromise before new sanctions are imposed on Iran.
The Brazilian president will be trying to encourage Iran to agree to a deal under which its existing stocks of enriched uranium are shipped out of the country and converted to fuel for a research reactor.
This will prevent the material from being available to make a nuclear bomb.
Iran has given mixed messages about such a deal, suggesting that it is still open to the idea, but then imposing conditions the West feels are unacceptable.
For his part, Iranian President Mahmoud Ahmadinejad will be hoping to persuade the Brazilians to use their seat on the UN Security Council to vote against new sanctions.
Mr Ahmadinejad had been hoping to have a similar conversation with the Turkish prime minister, but Turkey is now indicating that he probably will not travel to Tehran, possibly following pressure from Washington.
Iran has been mounting a big diplomatic effort to prevent the new sanctions – the foreign minister has been travelling to all 15 members of the security council.
But President Ahmadinejad is in a weak position following the dispute over his re-election last year.
It is not clear that he could deliver a compromise deal, even if he wanted to.
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