The Palestinian militant group's unprecedented assault triggered a devastating war in Gaza, drawing in Tehran-aligned militants across the Middle East and sparking rare direct attacks between Iran and Israel.

Iran, which supports Hamas financially and militarily, hailed the attack but denied any involvement.

"We did not know about October 7... We were supposed to have a meeting with the Americans on JCPOA renewal on October 9, which was undermined and destroyed by this operation," Zarif said at the World Economic Forum in Davos, using an acronym for the official name of the Iran nuclear deal negotiated in 2015.

Tehran's allies in the region, including Hamas, have "always worked for their own cause, even at our expense", Zarif said.

"We never tried to cash (in on) our investment in the region," he added.

Zarif, who is currently Iran's vice president for strategic affairs, was the foreign minister who negotiated the 2015 nuclear deal between Tehran and world powers.

In 2018, during US President Donald Trump's first term in office, Washington withdrew from the deal, which imposed curbs on Iran's nuclear programme in return for sanctions relief.

Tehran adhered to the deal until Washington's withdrawal, but then began rolling back on its commitments.

Iran has repeatedly expressed willingness to revive the accord.

Earlier this month, before Trump officially returned to the White House, Iranian officials held nuclear talks with counterparts from Britain, France and Germany.

Both sides described the talks as "frank and constructive".