World powers have sought to distance themselves from an alleged attack on Iran’s main uranium enrichment facility that threatens to complicate talks to revive an international nuclear deal with Tehran.

The US denied involvement in the incident at the Natanz underground site, while Germany warned the episode could harm the nuclear accord negotiations due to resume in Vienna on Tuesday.

Tehran has branded the problem with Natanz’s power supply “nuclear terrorism” and suggested Israel was behind it, although it has not confirmed speculation of a cyber attack. Iran has claimed those responsible aimed to derail efforts to restore the 2015 nuclear accord, which President Joe Biden has said the US is conditionally prepared to rejoin after the Trump administration withdrew in 2018. Israel has neither confirmed nor denied responsibility.

“We have seen reports of an incident at the Natanz enrichment facility in Iran,” a White House spokesperson said on Monday. “The US was not involved in any manner and we have nothing to add to speculation about the causes.”

Heiko Maas, Germany’s foreign minister, warned that the attack could damage prospects for the Vienna talks involving Iran and the other nuclear agreement signatories — China, Russia, the EU, Germany, France and the UK. The US attended the first round of negotiations last week, although it did not hold talks with Iran directly.

“What we are hearing currently out of Tehran is not a positive contribution, particularly the development in Natanz,” Maas told reporters on Monday.

Israel and Iran are widely understood to have targeted each other through cyber attacks in the past. The foreign ministry in Tehran said on Monday that “various sources” had suggested Israel was behind the Natanz incident, which damaged centrifuges used to enrich uranium.

News of the Natanz trouble emerged as Lloyd Austin, US defence secretary, began a trip to Israel. Austin also denied Washington was responsible.

Iranian authorities claimed the assault was aimed at undermining the nuclear deal, which Israeli prime minister Benjamin Netanyahu’s government opposes. Hossein Amir Abdollahian, an adviser to the Iranian parliament’s speaker on international affairs, said the timing of the Natanz incident was “not coincidental”.

“We have seen the enemies’ bloody claws many times before [despite being hidden in] their velvet gloves at the negotiating table,” he tweeted.

European diplomats expressed concern about the impact on delicate nuclear deal talks. Iran agreed under the accord to curbs on its atomic programme in exchange for the lifting of many international sanctions. Tehran launched an escalating series of breaches of the accord’s terms in 2019, in retaliation for the Trump administration’s decision to impose tough economic sanctions.

Ali Vaez, Iran director at the International Crisis Group, said any Iranian retaliation over Natanz could torpedo the renewed talks, although such an outcome seemed unlikely. “I doubt Iran would play into Israel’s hands by withdrawing from the nuclear negotiations,” he said. “But this would make it more difficult for Iranian negotiators to compromise. The best option for the US is to disassociate itself from this act of sabotage, which the Biden administration has already done.”