Iran has begun an airborne attack on Israel, the White House said and asserted that the US' support for Israel's security is "ironclad".

Israeli aviation authorities on Saturday said they are closing the country's airspace to all flights as it braces for an Iranian drone attack.

The US stands with the people of Israel and supports their defence against this threat from Iran, National Security Council's spokesperson at the White House Adrienne Watson said.

In a statement issued on Saturday, Watson also said this attack is likely to unfold over a number of hours. "Iran has begun an airborne attack against Israel" and President Joe Biden's team is in constant communication with Israeli officials as well as other partners and allies, the spokesperson said.

President Biden, who returned to Washington from his home in Delaware following the developments in the Middle East, will be meeting his national security team over the situation in the region, according to the statement. On his return, he was briefed about the developments by National Security Advisor Jake Sullivan and Principal Deputy National Security Advisor Jon Finer.

"His team is in constant communication with Israeli officials as well as other partners and allies. This attack is likely to unfold over a number of hours. President Biden has been clear: our support for Israel's security is ironclad. The United States will stand with the people of Israel and support their defence against these threats from Iran," Watson said.

Besides Sullivan and Finer, Defense Secretary Lloyd Austin, Secretary of State Antony Blinken, Chairman of the Joint Chiefs of Staff General Charles Q Brown, CIA Director Bill Burns, NIA Director Avril Haines, Counselor to the President Steve Ricchetti and National Security Council Coordinator for the Middle East and North Africa Brett McGurk will attend the meeting in-person at the White House's Situation Room.

Vice President Kamala Harris and Chief of Staff Jeff Zients will attend it using a secure video link.

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