Iranian diplomats said they held "frank and detailed" nuclear talks on Friday with counterparts from Germany, Britain and France, who have threatened to trigger sanctions if Tehran fails to agree a deal on uranium enrichment and cooperation with UN inspectors.

Diplomatic meeting in Istanbul between Tehran and E3 countries is first since Israel and US attacked Iran in mid-June.

European and Iranian diplomats have arrived in Istanbul in a renewed effort to resolve the standoff over Tehran's nuclear program. The talks mark the first formal engagement since June's 12-day war between Iran and Israel, a conflict that included U.S. airstrikes on Iranian nuclear facilities and heightened tensions across the region.