Israeli Prime Minister Benjamin Netanyahu has congratulated US President Donald Trump for his “courageous” decision not to recertify the Iran nuclear deal.

Mr Netanyahu said Mr Trump had created an opportunity to “fix this bad deal” and to roll back Iran’s aggression. He encouraged all other relevant nations to do the same.

Mr Netanyahu has been a fierce critic of the 2015 deal, which lifted sanctions on Iran in exchange for concessions regarding its nuclear program. He has long warned that it failed to address Iran’s support for militant groups who act against Israel.

Saudi Arabia also backed Mr Trump’s tough words.

In a statement the Saudi government said the kingdom welcomed Mr Trump’s “commitment to work with US allies in the region to face common challenges, particularly Iran’s aggressive policies.”

While Saudi Arabia says it supports the nuclear deal in place, it accuses Iran of exploiting the economic benefits of sanctions being lifted “to continue destabilising the region, especially through its ballistic missile development program and its support for terrorism in the region”.

The Sunni monarchy also names Iran’s backing of Shiite militias like Hezbollah in its statement of support for Mr Trump’s tougher stance.

But a senior Russian lawmaker said the decision not to recertify the nuclear agreement raises the danger of conflict.

Frants Klintsevich, deputy chairman of the defence committee in the upper house of parliament, told the Interfax news agency: “The creation of an unstable situation can lead to Iran reacting. With its resources and capabilities, Iran is a very serious country.”

Separately, Deputy Foreign Minister Sergei Ryabkov said there is a chance the two-year-old nuclear deal “will avoid a complete and destructive attack from its opponents, and it should be tried”.

European Union foreign policy chief Federica Mogherini said the deal is a robust agreement that is working and cannot be terminated by any leader, including Mr Trump.

She said the accord “is a robust deal that provides guarantees and a strong monitoring mechanism so that Iran’s nuclear program is, and will remain, exclusively for civilian purposes only”.

Ms Mogherini, who worked on behalf of major world powers to secure the deal, told reporters that “there have been no violations of any of the commitments”.

She underlined that Mr Trump cannot kill the deal, saying: “the President of the United States has many powers. Not this one”.

She added that the EU remains committed to the Iran nuclear pact.