Sullivan did not specify what those consequences might be, but he stopped short of urging restraint by Israel as the U.S. did in April when Iran carried out a drone and
missile attack on Israel.
Israeli Prime Minister Benjamin Netanyahu and a few other ministers were meeting in a bunker near Jerusalem, where the security cabinet was due to convene shortly, two Israeli officials said.
Iran said if Israel retaliated Tehran's response would be "more crushing and ruinous". Tehran targeted three Israeli military bases in its attack, Iran's state news agency said.
Oil prices shot up 5% on the news of the Iranian missile strikes, which raise the prospect of a wider war between the two arch enemies.
The previous round of Iranian
missiles fired at Israel in April - the first ever - were shot down with the help of the U.S. military and other allies. Israel responded at the time with airstrikes in Iran, but wider escalation was averted.
The Pentagon said the scope of Tuesday's airstrikes was about twice the size of April's assault.
ESCALATION IN LEBANON
Iran had vowed to retaliate following Israeli strikes that killed the top leadership of its ally Hezbollah in Lebanon, including the group's leader
Hassan Nasrallah, a towering figure in Iran's network of fighters across the region.
Hamas, the Iran-backed militant group in Gaza, praised the Iranian missile strikes, saying they avenged Israeli assassinations of three militant leaders, including Nasrallah.
In Washington, U.S. President Joe Biden said the United States was prepared to help Israel defend itself from Iranian missile attacks, and Sullivan said the president was tracking developments "minute by minute."
U.N. Secretary-General Antonio Guterres condemned what he called "escalation after escalation", saying: "This must stop. We absolutely need a ceasefire."
Israel in a post on X criticised Guterres for not holding "Iran responsible for firing 181 ballistic missiles at 10 million Israeli civilians."
Israel said overnight that its troops had launched ground raids into Lebanon, though it described the forays as limited.
In Beirut, Israeli strikes killed the commander of the Imam Hussein division, Israel's military said, referring to a Hezbollah-linked group based in Syria.
Nearly 1,900 people have been killed and more than 9,000 wounded in Lebanon in nearly a year of cross-border fighting, most in the past two weeks, according to Lebanese government statistics on Tuesday.
But a ground campaign into Lebanon for the first time in 18 years pitting Israeli soldiers against
Hezbollah, Iran's best-armed proxy force in the Middle East, would be a major regional escalation.
Source: Reuters