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 2015 Iran nuclear deal.

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 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 had 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".

"After withdrawing from the JCPOA, Iran has gained much more nuclear capability... based on American breakout calculations," Zarif said, while insisting that Tehran had never pursued a nuclear weapon.

"Had we wanted to build a nuclear weapon, we could have done it a long time ago. But a program to build nuclear weapons is not going to be like our program."

Zarif further expressed hopes that Trump would choose "rationality" and "be more serious, more focused, more realistic" in dealing with Iran during this term in office.