Iran's top nuclear negotiator, Ali Larijani, has canceled a visit to Europe, where he was supposed to hold talks on the international standoff over Iran's nuclear program.
Iran's official news agency, IRNA, said Larijani had to cancel the trip because he is ill.
The envoy had been scheduled to hold talks Friday, in Vienna with the head of the International Atomic Energy Agency, Mohamed ElBaradei.
Larijani was then to visit Germany to meet with German and European Union officials.
On Thursday, another Iranian envoy, Ali Akbar Velayati, traveled to Moscow for talks with Russian President Vladimir Putin. Mr. Putin expressed hope for a negotiated solution to the standoff over Iran's nuclear program.
The Russian president said last week that Moscow supports ElBaradei's proposal that calls for holding off on U.N. sanctions if Iran suspends its efforts to enrich uranium.
In December, Russia joined other members of the U.N. Security Council in imposing sanctions on Iran after it failed to meet a deadline to halt the sensitive nuclear work.
The U.S. and other Western powers accuse Iran of trying to build an atomic weapon, but Iran denies the claim, saying its nuclear program is only for peaceful purposes.
Some information for this report was provided by AFP and AP.