The killing of Soleimani could mark the “first step towards the end” of the Iran nuclear deal, German Foreign Minister Heiko Maas warned on Monday, a day after Iran announced it would no longer limit itself to the restrictions imposed by the pact.

The deal, known as the Joint Comprehensive Plan of Action or JCPOA, was implemented in 2016, freezing Iran's nuclear program in return for a progressive lifting of international sanctions. On Sunday, Iran announced that it would "set its limits based on its technical needs," essentially rendering the JCPOA redundant if technically still alive.

“What was announced is not in line with the nuclear agreement…[the situation] has not got easier, and this could be the first step towards the end of this agreement, which would be a big loss," Maas said in an interview with German public radio station Deutschlanfunk.

“We will now weigh this up very, very responsibly,” Maas added.

Iranians tear up a US flag during a demonstration in Tehran on January 3, 2020. Atta Kenare/AFP/AFP via Getty Images

According to Maas, European leaders joined US Secretary of State Mike Pompeo on a call over the weekend to discuss the situation. Maas said Pompeo “was not so pleased that [the European leaders] did not agree one hundred percent” with the US position.

Meanwhile, EU foreign affairs chief Josep Borrell reiterated the EU’s call for the “full implementation” of the JCPOA agreement, expressing in a tweet shared on Monday his “regret” that Iran had decided to continue enriching uranium without limitation.

“Full implementation of [the] Nuclear Deal by all is now more important than ever, for regional stability & global security,” Borrell tweeted.

The move marks Iran's fifth step in a gradual divorce from the nuclear deal, having chipped away at its provisions in response to the US withdrawal from the deal and re-imposition of tough sanctions. It now no longer recognizes any limits on the operational aspects of its nuclear program, including in enrichment capacity, the extent (or degree) of enrichment, and nuclear research and development.