Agencies Vienna

Iran has further increased its stockpile of uranium enriched to near weapons-grade levels, a confidential report by the UN nuclear watchdog said on Saturday and called on Tehran to urgently change course and comply with the agency's probe. 

The report comes at a sensitive time as Tehran and Washington have been holding several rounds of talks over a possible nuclear deal that US President Donald Trump is trying to reach.

The report by the Vienna-based International Atomic Energy Agency - which was seen by The Associated Press - says that as of May 17, Iran has amassed 408.6 kilogrammes of uranium enriched up to 60 per cent. That's an increase of 133.8 kilogrammes since the IAEA's last report in February.

That material is a short, technical step away from weapons-grade levels of 90 per cent. A report in February put the stockpile at 274.8 kilogrammes. The IAEA chief Rafael Mariano Grossi has stressed repeatedly that "Iran is the only non-nuclear weapon state enriching to this level". On Saturday, Grossi said he "reiterates his urgent call upon Iran to cooperate fully and effectively" with the IAEA.

On Thursday, senior Iranian officials emphasised that any agreement must fully lift sanctions and allow the country's nuclear program to continue. The comments came a day after Trump said he has told Israeli Prime Minister Benjamin Netanyahu to hold off on striking Iran to give the US administration more time to push for a new nuclear deal with Tehran.