The United States pledged to support Israel's defense against an Iranian drone attack Saturday as President Joe Biden held crisis talks with his top national security team.
Biden cut short a weekend trip to Delaware as fears grew of an attack -- news of which broke as the president was still in his helicopter on his way back to Washington.
The White House said that "Iran has begun an airborne attack against Israel" and that it was "likely to unfold over several hours."
"President Biden has been clear: our support for Israel's security is ironclad," National Security Council spokesperson Adrienne Watson said in a statement.
"The United States will stand with the people of Israel and support their defense against these threats from Iran."
Biden was kept regularly updated and his team was in "constant communication" with the Israelis and other allies, Watson said.
Biden was due to meet in the White House's heavily secured situation room with his top officials including Defense Secretary Lloyd Austin, Secretary of State Antony Blinken and CIA chief Bill Burns, the White House added.
Iran had vowed retaliation after a presumed Israeli strike on April 1 leveled an Iranian diplomatic building in Damascus, killing seven members of the elite Revolutionary Guards including two generals.
Israel's army had said earlier that Iran had launched direct drone strikes at it. Iran's Revolutionary Guards later confirmed that an attack was underway and Iranian state TV said it involved "drones and missiles."
The US president, wearing a blue baseball cap, made no comment to waiting reporters as he boarded his helicopter Marine One in Rehoboth Beach, Delaware, to fly back to Washington.
After his arrival, Biden went straight to the Oval Office.
He had been due to stay in the coastal town where he keeps a house on Sunday, but cut the trip short for consultations on the Middle East situation, the White House said.
Biden had arrived in Rehoboth less than 24 hours earlier, shortly after warning Iran not to attack Israel but saying he expected an attack sooner rather than later.
Earlier Saturday, White House National Security Advisor Jake Sullivan said he spoke with his Israeli counterpart Tzachi Hanegbi to emphasize Washington's "ironclad" support.
Defense chief Austin also spoke to his Israeli counterpart and "made clear that Israel could count on full US support to defend Israel against any attacks by Iran and its regional proxies," the Pentagon said.
Tensions had ratcheted up earlier in the day when Iran's Revolutionary Guards seized a container ship near the Strait of Hormuz that was "related to the Zionist regime," the term it uses for Israel, state media reported.
The White House condemned the seizure of the British-owned vessel.
"We call on Iran to release the vessel and its international crew immediately," Watson said.
"Seizing a civilian vessel without provocation is a blatant violation of international law, and an act of piracy by the Islamic Revolutionary Guards Corps."
On Thursday the Pentagon said the top US commander for the Middle East had traveled to Israel for talks on security threats with the country's military officials.
The Strait of Hormuz connects the Gulf with the Indian Ocean and, according to the US Energy Information Administration, more than a fifth of global oil consumption passes through it each year.
