Vienna: Iran has said that it will allow UN 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.
In meetings with IAEA officials earlier this month, Tehran agreed "in principle" to allow them to strengthen monitoring and containment measures to improve chances of detecting any diversion of nuclear material for military use, diplomats said.
"Now an agreement has been reached for enhanced surveillance measures. But we have to see if and when they are put in place," a senior Western diplomat said.
The Islamic Republic said its promise showed it was cooperating well with the IAEA.
Western diplomats welcomed the concession, but said that these were routine steps that Tehran had shirked.
Iran says it is enriching uranium to 20 percent purity to create material for fabrication into fuel for a medical research reactor.
This has drawn suspicion abroad, as Tehran is thought to lack the technology to complete such a plan soon.
Since the work started, the IAEA has sought to improve camera surveillance angles, add cameras, conduct more frequent visits and inspections at short notice at the site and to add equipment to measure enrichment levels, diplomats said.
The UN watchdog had wanted these measures in place before the start of higher-grade enrichment at the site nearly three months ago.