U.S. President Joe Biden said on Friday that Iran's enrichment of uranium to 60% purity is not helpful but said he is pleased Tehran is still in indirect talks with the U.S. about both countries resuming compliance with the 2015 nuclear deal, officially called the Joint Comprehensive Plan of Action (JCPOA).

Iran on Friday said it had begun enriching uranium to 60%, its highest level ever, at its Natanz plant, where an explosion occurred earlier this week that Tehran blamed on Israel. President Hassan Rouhani said the move is a response to sabotage at the Natanz nuclear facility.

"We do not support and do not think it's at all helpful that Iran is saying it's going to move to enrich to 60 percent," Biden told reporters in Washington during a joint news conference with Japanese Prime Minister Yoshihide Suga.

"We are, though, nonetheless pleased that Iran has continued to agree to engage in discussions - indirect discussions - with us and with our partners on how we move forward and what is needed to allow us to move back into the (nuclear deal)," Reuters quoted Biden as adding.

Iran had in recent months already raised enrichment to 20% purity.

A 2015 deal with world powers had capped Iran’s level of purity at 3.67% in return for the termination of economic and financial sanctions.

"We are producing about 9 grams of 60% enriched uranium an hour," Ali Akbar Salehi, head of the Atomic Energy Organization of Iran, told national television.

"But we have to work on arrangements ... to drop it to 5 grams per hour. But then we will simultaneously produce 20% (uranium)," Salehi said.

Earlier, Iran's parliament speaker Mohammad Baqer Qalibaf said Iranian scientists had successfully started enriching 60% uranium at 40 minutes past midnight.

"The will of the Iranian nation makes miracles that thwart any conspiracy," Qalibaf wrote on Twitter.

In Vienna, a spokesman for the United Nations nuclear watchdog IAEA declined to comment on the Iranian statements about 60% enrichment.

Asked if Iran's move was a sign that Tehran is not serious about returning to the nuclear deal, Biden replied: "The discussions are underway. I think it's premature to make a judgment as to what the outcome will be. But we are still talking."

Iran and global powers are meeting in Vienna to try to rescue the 2015 nuclear deal abandoned by former U.S. President Donald Trump three years ago.

The talks will carry on for several days before breaking so that Iranian and U.S. officials can return home for consultations, a European Union official said on Friday.  

"We have this (Iranian) decision to go for 60% enrichment. Obviously, this is not making the negotiation easier," the EU official told reporters, calling what happened at Natanz "deliberate sabotage".

Abbas Araqchi, Iran's chief negotiator at the talks, said on Tuesday that Iran would activate 1,000 advanced centrifuge machines at Natanz.

Multiple Israeli media outlets have quoted unnamed intelligence sources as saying the country's Mossad spy service carried out the sabotage operation at the Natanz complex. Israel - widely believed to be the only West Asian country with a nuclear arsenal - has not formally commented on the incident.

Israeli Foreign Minister Gabi Ashkenazi said on April 16 that Israel will do "whatever it takes" to ensure that Iran does not acquire what he called “nuclear weapons”. 

 In a tweet on Wednesday, Iranian Foreign Minister Mohammad Javad Zarif said the “nuclear terrorism” at Natanz “has unleashed a dangerous spiral that can only be contained” by ending the “economic terrorism” that started against Iran during Donald Trump’s presidency.

Biden and his vice president Kamala Harris have a clear choice and that is either restore the Obama-era nuclear deal or follow Trump’s “maximum failure” campaign, Zarif asserted.

The chief diplomat, who helped craft the 2015 nuclear deal – JCPOA-   said there is “no alternative” other than choosing one of these two approaches.

At the same time, Zarif warned the Biden administration that “no much time” left to revive the nuclear deal.

PA/PA