The United States and Iran are set to begin a third round of nuclear talks this weekend, entering what experts describe as a more difficult phase of technical negotiations as Washington lays out stricter conditions.

Iranian Foreign Minister Abbas Araqchi said on Thursday he was ready to travel to Europe for talks on Tehran's nuclear programme, with France indicating European powers were also ready for dialogue if Tehran showed it was seriously engaged.

That the talks are even happening represents a historic moment, given the decades of enmity between the two countries.