President Joe Biden is "deeply concerned" about a leak of classified documents that contain the US's assessment of Israeli plans to attack Iran, White House National Security Council spokesman John Kirby said. Officials have not determined whether the documents were released due to a hack or a leak, Mr Kirby said.

The US is investigating a leak of highly classified US intelligence about Israel’s plans for retaliation against Iran, according to three people familiar with the matter. One of the people familiar confirmed the documents’ authenticity.

President Biden is "deeply concerned" by the possible leak of U.S. intelligence documents regarding Israeli preparations for an attack on Iran, spokesman John Kirby said Monday.

The low-boil conflict between Israel and Iran has shaped the Middle East for decades. Of the many conflicts that have roiled the region, theirs has long been among the most explosive. The two have attacked each other — mostly quietly and in Iran’s case often by proxy — while avoiding an escalation into direct war.

Hezbollah launched a barrage of rockets into central Israel on Tuesday, setting off air raid sirens in the country’s most populated areas but causing no apparent damage or injuries

U.S. Secretary of State Antony Blinken will make another push for a ceasefire when he heads to the Middle East on Monday, the State Department said, seeking to kickstart negotiations to end the Gaza war and also defuse the spillover conflict in Lebanon.

Blinken's week-long trip comes as the region braces for Israel's response to Iran's Oct. 1 ballistic missile attack on Israel. The retaliation could disrupt oil markets and risks igniting a full-blown war between the arch-enemies.