Iran has launched dozens of drones and missiles at Israel, the country’s Islamic Revolutionary Guard Corps (IRGC) confirmed, after Israel said Tehran had begun attacks.

The IRGC said on Saturday that it had released the drones and missiles under the operation “True Promise”, adding that the move was part of the punishment for “Israeli crimes”.

Israel said the drones would take several hours before reaching its airspace.

The strikes come nearly two weeks after an Israeli ayyack on the Iranian consulate in Syria killed seven IRGC members.

“We launched an operation using drones and missiles in response to the Zionist entity’s crime of targeting the Iranian consulate in Syria,” the IRGC said in a statement.  “The operation was carried out with dozens of missiles and drones to strike specific targets in the occupied territories.”

Speaking in televised address on Saturday, Israel’s army’s spokesman, Daniel Hagari, said: “Iran launched UAVs [unmanned aerial vehicles] from its territory towards the territory of the state of Israel.  “This is a severe and dangerous escalation. Our defensive and offensive capabilities are at the highest level of readiness ahead of this large-scale attack from Iran.”

Israel has been on heightened alert since its strike on Damascus on April 1, even though it did not comment on that attack. Iran pledged revenge and a retaliatory attack had been expected.

Israeli Prime Minister Benjamin Netanyahu said on Saturday that Israel was prepared for a “direct attack from Iran”.

Minister of Defence Yoav Gallant said Israel was “closely monitoring a planned attack” against it by Iran and its allies in the region.

United States President Joe Biden, who on Friday warned Iran against attacking Israel after saying such a scenario appeared imminent, has pledged to stand with Israel against Iran, the White House said.

US National Security Council spokesperson Adrienne Watson said in a statement that Biden is regularly updated by his national security team and is in constant communication with Israeli officials, US partners and allies.

Syria also put on high alert its Russian-made Pantsir ground-to-air defence systems around the capital Damascus and major bases in the event of an Israeli strike, army sources told the Reuters news agency.

Meanwhile, Iraq, Jordan, Lebanon and Israel announced they had temporarily closed their airspace.

A retired Israeli general, Amos Yadlin, told the country’s Channel 12 news that the Iranian drones were equipped with 20 kg (44 pounds) of explosives each.

Israel’s military said sirens would sound in any threatened areas and that its defences were poised to deal with them.  “We know that planes are patrolling in the skies above Israel, we know that Benjamin Netanyahu is meeting with his war cabinets, his security cabinets this evening,” said Al Jazeera’s Rory Challands, reporting from occupied East Jerusalem.

“This is a country… waiting for those drones to arrive,” he added.

Challands said that although Haggari did not confirm how long it would take, “it will have to go through several countries’ airspace … They could take about nine hours to arrive”.

Israel’s war on Gaza, now in its seventh month, has driven up tensions in the region, spreading to fronts with Lebanon and Syria and drawing long-range fire at Israeli targets from as far away as Yemen and Iraq.

Earlier on Saturday, Iranian armed forces seized a container ship linked to Israel near the Strait of Hormuz.

(Aljazeera)