VIENNA -- The Latest on Iran's unraveling nuclear deal with world powers (all times local):
Israeli Prime Minister Benjamin Netanyahu says Iran's move to break limits on its stockpile of low-enriched uranium is a "significant step toward making a nuclear weapon."
Netanyahu said Monday that Israel would "soon unveil more proof that Iran was lying all the time" about its nuclear program.
The Israeli prime minister has been an outspoken critic of Iran and has long accused Tehran of seeking to develop nuclear weapons. Iran has insisted that its nuclear program was for peaceful purposes.
Last year Netanyahu presented what he said was a secret Iranian nuclear archive proving that Tehran had lied about pursuing nuclear arms.
Netanyahu is calling upon European countries to "stand by your commitments" to impose sanctions against Iran if it violates the nuclear agreement reached with world powers in 2015.
Britain is urging Iran to reverse course and stick to the terms of the nuclear deal it signed with world powers.
Foreign Secretary Jeremy Hunt said he was "deeply worried" by Iran's announcement that it had surpassed the stockpile of low-enriched uranium allowed under the 2015 agreement, known as the Joint Comprehensive Plan of Action.
In a tweet, he urged Tehran "to avoid any further steps away from JCPoA & come back into compliance."
Prime Minister Theresa May's spokesman, James Slack, said the announcement was "extremely concerning."
It comes after the U.S. unilaterally withdrew from the agreement and imposed heavy new sanctions on Iran.
Slack said Britain will continue working with the remaining signatories, particularly France and Germany, to keep the deal in place.
A senior Russian diplomat says that U.S. sanctions have provoked Iran's move to break the limit set on its uranium stockpiles.
Iran acknowledged Monday it had exceeded the limit set on its low-enriched uranium stockpiles by a 2015 nuclear deal with world powers, its first major departure from the agreement a year after Washington unilaterally withdrew from it.
Russia's Deputy Foreign Minister Sergei Ryabkov noted that Iran had warned of its move in advance. He urged all parties to "avoid escalation," saying that Iran's move "causes regret, but shouldn't be overdramatized."
Ryabkov said the development is a "natural result" of the U.S.'s maximum pressure campaign.
He added that Iran was facing "unprecedented and unthinkable" U.S. sanctions, including an oil trade embargo, which are an attempt to "strangle" the country.
The United Nations' atomic watchdog agency is confirming Iran has surpassed the stockpile of low-enriched uranium allowed under the 2015 nuclear deal with world powers.
The International Atomic Energy Agency said its director general, Yukiya Amano, has informed its board of governors that the organization had verified Monday Iran's stockpile of uranium enriched up to 3.67% had exceeded the 300 kilograms allowed.
Iran earlier in the day had announced that it had exceeded the limit, as it threatened it would.
Last year, the U.S. unilaterally pulled out of the nuclear deal known as the Joint Comprehensive Plan of Action.
The other signatories — including the UK, France and Germany — involved have been struggling to keep Iran within the deal.
The deal promises Iran economic and sanctions relief for limits on its nuclear program .