VIENNA - Iran has said that it will allow United Nations nuclear officials better monitoring and access to a site where it started enriching uranium to higher levels over two months ago, diplomats said.

The move should have happened earlier, diplomats said, as Iran started higher enrichment in February, before inspectors from the International Atomic Energy Agency (IAEA) could improve surveillance.

Suspecting that Iran aims to develop atomic weapon, Western powers have said the switch to higher enrichment was "provocative" and warranted sanctions.