Iran's national airliner Iran Air will buy five Tupolev passenger planes from Russia to meet high demand for domestic flights, Iran's state broadcaster said on Wednesday.

"Iran Air has various plans to complete its fleet and is to buy five Tupolev 214 passenger planes," Managing Director Saeed Hessami was quoted as saying on the web site of state broadcaster IRIB.

"The deposit has been prepared for transfer to the (Ilyushin Finance) company and they (the aircraft) will gradually join the fleet," Hessami said without giving any financial details on the deal.

Hessami did not mention any other plans to buy Tupolev planes from Russia.

In Moscow on Monday, a source with knowledge of the deal said Iran had started talks to buy 30 Russian Tupolev 204 passenger aircraft worth more than USD$1 billion.

The source, who asked not to be identified, said the deal was likely to be reached by the end of the year.

It is likely to embarrass Western powers which are trying to persuade Russia and China to join them in tightening sanctions on Iran to make it halt its uranium enrichment program.

Washington and its close allies suspect it of trying to build nuclear weapons, but Tehran says it wants only to produce electricity.

Russia and China, both with strong trade ties with Tehran and veto power on the UN Security Council, have argued for more negotiations to encourage Iran to comply with the international demand for a halt in uranium enrichment.

Government-owned Iran Air operates a fleet of Boeing and Airbus planes, while its Iran Air Tours subsidiary flies Tupolev 154 planes. Iran's airline sector has been under US sanctions for almost three decades, preventing it from buying new US planes or spare parts.