Iran negotiator on ongoing nuclear talks in Vienna

Before the next round of nuclear talks between Iran and world powers in Vienna, Iranian nuclear negotiator Abbas Araghchi told state TV that negotiations must not drag on.

Araghchi said negotiators have held tight informal meetings over the past two days.

He added that Iranians would only continue talks that are going forward in a constructive direction and they don't want "negotiations for the sake of negotiations only".

Negotiations to bring the United States back into a landmark nuclear deal with Iran are set to resume Thursday in Vienna amid signs of progress - but also under the shadow of an attack this week on Iran's main nuclear facility.

Iran announced on Tuesday that it would begin enriching uranium up to 60% purity after an attack on its Natanz nuclear facility, pushing its program to higher levels than ever before though still remaining short of weapons-grade.

The announcement marks a significant escalation after the sabotage that damaged centrifuges, suspected of having been carried out by Israel - and could inspire a further response from Israel amid a long-running shadow war between the nations.

Israeli Prime Minister Benjamin Netanyahu has vowed never to allow Tehran to obtain a nuclear weapon and his country has twice preemptively bombed Mideast nations to stop their atomic programs.

On Tuesday, Iran's foreign minister had warned that the assault at Natanz could hurt ongoing negotiations over its tattered atomic deal with world powers.

Those talks are aimed at finding a way for the United States to re-enter the agreement, the goal of which is to limit Iran's uranium enrichment in exchange for relief on sanctions.