The Istanbul meeting follows Foreign Minister Abbas Araghchi's warning of "irreversible" consequences if the European powers move to reimpose United Nations sanctions on Iran that were lifted under a 2015 deal.

The so-called E3 were parties to that agreement along with China, Russia and the United States.

But Trump effectively torpedoed the deal during his first term in 2018, by unilaterally abandoning it and reimposing sanctions on Iran's banking sector and oil exports.

A year later, Iran responded by rolling back its own commitments under the deal, which provided relief from sanctions in return for UN-monitored restrictions on Iran's nuclear activities.

The three European powers have been weighing whether to trigger the 2015 deal's "snapback" mechanism, which would reinstate UN sanctions in response to Iranian non-compliance -- an option that expires in October.

Such a stance "risks provoking a global nuclear proliferation crisis that would primarily affect Europeans themselves, Iran's top diplomat warned.

However, writing in the French weekly Le Point, he also noted that Tehran was "ready to turn the page" in its relations with Europe.

Friday's meeting with the European powers comes less than a week after a fourth round of Iran-US nuclear talks which Tehran called "difficult but useful", and after which a US official said Washington was "encouraged".

Araghchi said Friday's talks will be at deputy foreign ministers level.