VIENNA, May 27 (Reuters) - Iran has stayed within the limits of a nuclear deal it reached with six world powers last year on its stockpiles of uranium and heavy water, two chemicals that could be used in an atomic weapons programme, the U.N. nuclear agency said on Friday.

In exchange for sanctions relief, Iran last July committed to keeping its stockpile of low-enriched uranium below 300 kg (662 pounds) and its stock of heavy water, a non-radioactive product, at less than 130 metric tonnes.

"Throughout the reporting period, Iran had no more than 130 metric tonnes of heavy water... Iran's total enriched uranium stockpile did not exceed 300 kg," the International Atomic Energy Agency (IAEA) said in a quarterly report on Iran.

The IAEA is in charge of policing the nuclear deal.

(Reporting By Shadia Nasralla; editing by Francois Murphy) ((; +43 153 11 2256; +43 664 390 6505;))