VIENNA: Diplomats said Thursday that the latest talks in Vienna to save the 2015 Iran nuclear deal were positive despite fresh tensions over Tehran’s announcement that it was preparing to ramp up uranium enrichment in response to an attack on a facility it blamed on arch-foe Israel.

The latest round of diplomatic negotiations aimed at ensuring the US’s return to the accord lasted for roughly two hours on Thursday afternoon, with Russia’s ambassador to the UN in Vienna, Mikhail Ulyanov, tweeting afterwards that the “general impression is positive”.

The talks comprised delegations from the remaining parties to the deal following the US exit — Germany, France, Britain, China, Russia and Iran.

There had been fears that developments in recent days could cast a pall over the talks, with a European diplomat telling AFP ahead of the meeting that Iran’s announcement that it would enrich uranium up to 60 percent “puts pressure on everyone”.

The move would take Iran closer to the 90 percent purity level needed for use in a nuclear weapon.

Tehran says the enrichment move is a response to Israel’s “nuclear terrorism” after an explosion on Sunday knocked out power at its Natanz enrichment plant. Israel has neither confirmed nor denied involvement, but public radio reports in the country said it was a sabotage operation by the Mossad spy agency, citing unnamed intelligence sources.

Despite the latest developments on the ground, the chair of the talks, EU diplomat Enrique Mora, also struck an upbeat note at the end of Thursday’s meeting. He tweeted that participants had been “ready to advance... despite very challenging events and announcements over the past days”.