US President Joe Biden pledged to never allow Iran to develop nuclear weapons, in comments ahead of a meeting with Israel's outgoing President Reuven Rivlin on Monday.

"What I can say to you: Iran will never get a nuclear weapon on my watch," Biden said ahead of the White House meeting.

The US president also told Rivlin, who is due to leave office on July 9, that his country "remains determined to counter Iran's malign activity and support for terrorist proxies, which have destabilizing consequences for the region," according to a readout from their meeting.

Biden's comments came a day after he ordered strikes on sites used by Iranian-backed militia groups on the Iraq-Syria border. The groups were responsible for attacks on US personnel in Iraq, Biden said.

Negotiations are under way to try to salvage the 2015 Iran nuclear deal.
After the US unilaterally withdrew from the international nuclear agreement in 2018, Tehran turned its back on the limitations the deal placed on its nuclear programme.

The Islamic Republic then gradually expanded its nuclear activities in contravention of the agreements and restricted international nuclear inspections.

Diplomats from Germany, France, Britain, Russia and China have been trying to mediate between the US and Iran at talks under way in Vienna since April, aiming to save the nuclear pact.

Former US president Donald Trump, who chose to back out of the deal, and Israel's former prime minister Benjamin Netanyahu, who repeatedly criticized the agreement, have both now been replaced and the US and Israel are adjusting their relations.

Israel's new Foreign Minister Yair Lapid said earlier this week the two countries would fix mistakes made over the past few years, but stressed he had "serious" concerns about the negotiations for the US to return to the nuclear agreement.

The White House on Monday said that Biden extended an invitation for new Prime Minister Naftali Bennett "to meet with him soon at the White House and reaffirmed that this administration looks forward to close collaboration with the new Israeli government on the many important issues on the bilateral agenda."