NEW YORK: Iran's mission to the United Nations said on Sunday that Tehran was not involved in one of the bloodiest attacks in Israel's history when Islamist group Hamas killed 700 Israelis and abducted dozens more.

"The resolute measures taken by Palestine constitute a wholly legitimate defense against seven decades of oppressive occupation and heinous crimes committed by the illegitimate Zionist regime," Iran's U.N. mission said in statement.

Iran has made no secret of its backing for Hamas, funding and arming the group and another Palestinian militant organisation Islamic Jihad.

The Hamas assault on Saturday, the biggest incursion into Israel in decades, coincided with U.S.-backed moves to push Saudi Arabia towards normalising ties with Israel in return for a defence deal between Washington and Riyadh, a move that would slam the brakes on the kingdom's rapprochement with Tehran.

"We emphatically stand in unflinching support of Palestine; however, we are not involved in Palestine's response, as it is taken solely by Palestine itself," Iran's U.N. mission said.

Hamas fighters' rampage through Israeli towns on Saturday was the deadliest such incursion since Egypt and Syria's attacks in the Yom Kippur war 50 years ago and has threatened to ignite another conflagration in the long-running conflict.

Iran's U.N. mission said the "success" of the Hamas operation was because it was a surprise, which makes it the "biggest failure" of Israel's security organizations.

"They are attempting to justify their failure and attribute it to Iran's intelligence power and operational planning," Iran's U.N. mission said.

In response to the Hamas attacks, Israeli air strikes have hit housing blocks, tunnels, a mosque and homes of Hamas officials in Gaza, killing more than 400 people, including 20 children.

"They (Israel) find it very difficult to accept that in the intelligence community, it is being narrated that they were defeated by a Palestinian group," said Iran's U.N. mission.