Russia has delivered its first shipment of nuclear fuel to a reactor it is helping to build at Bushehr in Iran.
The two sides reached agreement last week on a schedule to finish building the plant after years of delays.
The delivery of the nuclear fuel has removed one of the most significant practical sanctions against Tehran, says the BBC's diplomatic correspondent, Jonathan Marcus.
Russia urged Iran to stop enriching uranium, saying there was no longer any need.
But a senior Iranian official said his country would not halt uranium enrichment under any circumstances, Reuters news agency said.
clipped from: news.bbc.co.uk