Diplomats on both sides say the low-profile technical meeting can be ideal for thrashing out details and a timeline for the first steps to limit Iran’s most sensitive nuclear work, ahead of a fifth round of top-level nuclear talks in early April.

The technical meeting comes as President Barack Obama travels this week to the Middle East, where Iran’s nuclear program – and Israel’s consideration of any future Iranian nuclear weapon to be an “existential threat” – will be high on the agenda.

On the table in Istanbul will be a revised proposal by the six world powers that requires Iran to “suspend” but not permanently halt its 20-percent uranium enrichment, and to disable work at the deeply buried Fordow facility, in exchange for modest relief from sanctions.

That offer was put to Iran in Almaty, Kazakhstan, late last month, and is an easing of a first proposal – described at the time as “maximalist” by Western diplomats – put to Iran last spring.