Iran on Wednesday said its missile attack on Israel, its biggest military assault on the country, was over, barring further provocation, while Israel and the United States promised to hit back as fears of a wider war intensified.

Israel threatened to launch a "significant retaliation" within days that could target oil production facilities inside Iran and other strategic sites, US news website Axios reported on Wednesday citing Israeli officials.

Despite calls for a ceasefire from the United Nations, the US and the European Union, fighting between Israel and the Lebanon-based Hezbollah continued on Wednesday.

Israel renewed its bombardment of Beirut's southern suburbs, a stronghold of the Iran-backed group, with at least a dozen airstrikes against what it said were targets belonging to the group.

Large plumes of smoke were seen rising from parts of the suburbs. Israel issued new evacuation orders for the area, which has largely emptied after days of heavy strikes.

Hezbollah said it confronted Israeli forces infiltrating the Lebanese town of Adaisseh early on Wednesday and forced them to retreat.

Iran said Tuesday's assault on Israel was solely aimed at military facilities. Iran's state news agency said three Israeli military bases had been targeted.

Tehran said its assault was a response to Israeli killings of militant leaders and aggression in Lebanon against Hezbollah and in Gaza.

"Our action is concluded unless the Israeli regime decides to invite further retaliation. In that scenario, our response will be stronger and more powerful," Iranian Foreign Minister Abbas Araqchi said in a post on X early on Wednesday.

Israeli Prime Minister Benjamin Netanyahu has vowed to strike back. "Iran made a big mistake tonight - and it will pay for it," he said at the outset of an emergency political security cabinet meeting late on Tuesday, according to a statement.

Washington said it would work with Israel to ensure Iran faced "severe consequences" for Tuesday's attack, which Israel said involved more than 180 ballistic missiles.

US Secretary of Defence Lloyd Austin spoke to Israeli Defence Minister Yoav Gallant late on Tuesday and said Washington was "well-postured" to defend its interests in the Middle East, the Pentagon said in a statement.

"The minister and I expressed mutual appreciation for the coordinated defense of Israel against nearly 200 ballistic missiles launched by Iran and committed to remain in close contact," Austin said separately in a post on X.

US Navy warships fired about a dozen interceptors against Iranian missiles headed toward Israel, the Pentagon said. Britain said its forces played a part "in attempts to prevent further escalation in the Middle East", without elaborating.

The Pentagon said Tuesday's airstrikes by Iran were about twice the size of April's assault by Iran on Israel.

These developments came as Israeli strikes killed at least 32 people in southern Gaza overnight as the military launched ground operations in Khan Younis, Palestinian medical officials said on Wednesday.

Israel has continued to strike what it says are militant targets across Gaza nearly a year after Hamas’ October 7 attack ignited the war, even as attention has shifted to Lebanon, where Israel is battling Hezbollah, and to Iran and its missile attacks. (Agencies)