"This time (we want) only action from the other side, and we will also act", he said, strengthening demands that the USA must lift all sanctions if it wants Iran to live up to its prior commitments.
"The E3 and the United States are united in underlining the risky nature of a decision to limit IAEA access, and urge Iran to consider the consequences of such grave action, particularly at this time of renewed diplomatic opportunity".
On 7 February, in his first interview since taking office last month, Biden ruled out the prospect of lifting sanctions on Iran until it stopped enriching uranium.
"It is not surprising that Iran continues to demonstrate its willingness to leave the agreement if the United States does not return to it", the diplomat said, noting that the nuclear threat "is by far the most important".
Despite the warning to Iran, the US-European statement had lauded the nuclear accord.
The chancellor also said that "now was the time for positive signals that create trust and increase the chances of a diplomatic solution", he added.
Teheran has set a deadline of next week for Biden to begin reversing sanctions imposed by Trump, or says it will take its biggest step yet to breach the deal - banning short-notice inspections by the United Nations nuclear watchdog permitted under an Additional Protocol. Specifically, Tehran says it will halt snap nuclear inspections outside of its declared sites as of 23 February.
German Foreign Minister Heiko Maas puts on his face mask at the end of a press conference in Berlin, Germany, December 21, 2020.
FILE - This photo released November 5, 2019 by the Atomic Energy Organization of Iran shows centrifuge machines at the Natanz uranium enrichment facility in central Iran.
An IAEA report on Wednesday said Iran had informed the IAEA of plans to install more of its advanced IR-2m centrifuges at its main underground enrichment plant at Natanz, in a further move apparently meant to pile pressure on Washington.
Iran has set a deadline of next week for Biden to begin reversing sanctions imposed by former president Trump, or it will ban short-notice nuclear inspections.
Last month, Iran began enriching uranium to levels unseen since before it signed the 2015 deal, which eased economic sanctions against the country in exchange for Tehran agreeing to curb its nuclear ambitions.
Grossi, who heads the UN-backed nuclear watchdog group, seeks to foster an agreement allowing the continuation of the agency's inspections and verification activities in the country, the organization said Wednesday.
Tehran has been using its violations of the nuclear deal to increase pressure on the JCPOA's remaining signatories, France, Germany, Britain, Russia and China, to provide additional incentives to Iran to offset the crippling American sanctions re-imposed after the U.S. pulled out of the agreement in 2018.
But Tehran rejected this precondition, pressing on with increasing nuclear work in retaliation for Trump's so-called "maximum pressure" sanctions policy to weaken the Iranian regime which has had no relations with Washington for four decades. "They are playing with fire", he says. "The Additional Protocol is a step beyond safeguards".
"Iran's envoy to the IAEA said on Wednesday that the agency's director general, Rafael Grossi, would visit Tehran on Saturday to discuss the country's plan to scale back cooperation with inspectors next week".