JERUSALEM/BEIRUT: The Israeli military said on Wednesday that regular infantry and armoured units were joining ground operations in southern Lebanon, stepping up pressure on Hezbollah, as Israel prepared to retaliate against a barrage of Iranian missile strikes.

Already battling Hamas in Gaza, Israel is beefing up its presence in south Lebanon in its conflict with Hezbollah a day after it was attacked by Iran, raising fears the oil-producing Middle East could be engulfed in a wider conflict.

The addition of infantry and armoured troops from the 36th Division, including the Golani Brigade, the 188th Armoured Brigade and 6th Infantry Brigade, suggests that the operation has moved beyond limited commando raids.

The military has said the ground operation is largely aimed at destroying tunnels and other infrastructure on the border and there were no plans for a wider operation targeting Beirut or major cities in southern Lebanon.

Iran said on Wednesday 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.

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

Despite calls for a ceasefire from the United Nations, the United States 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.

NEW EVACUATION ORDERS

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.

Nearly 1,900 people have been killed and more than 9,000 wounded in Lebanon in almost a year of cross-border fighting, with the most in the past two weeks, Lebanese government statistics showed on Tuesday.

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

Iran's missile strikes and Israel's operations in Lebanon have caused alarm around the world, as Tehran's Middle East proxies -- Hezbollah, Yemen's Houthis and armed groups in Iraq -- launched attacks in support of Hamas.

German Chancellor Olaf Scholz called on Iran and Hezbollah to immediately end their attacks on Israel and warned that Iran risks inflaming the entire region.

Japan said it is deeply concerned by the situation.

Iran said Tuesday's assault on Israel was solely aimed at military facilities and was a response to Israeli killings of leaders including Hezbollah chief Hassan Nasrallah and aggression in Lebanon against the group and in Gaza. Iran's state news agency said three Israeli military bases had been targeted.

"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, saying Iran will pay a heavy price.

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

U.S. Secretary of Defense 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 Pentagon said Tuesday's airstrikes by Iran were about twice the size of April's assault by Iran on Israel.

'THE RESPONSE WILL BE PAINFUL'

Israel activated air defences against Iran's bombardment on Tuesday and most missiles were intercepted "by Israel and a defensive coalition led by the United States," Israeli Rear Admiral Daniel Hagari said in a video on X.

"Iran's attack is a severe and dangerous escalation," he added.

In a statement on state media, the general staff of Iran's armed forces said any Israeli response would be met with "vast destruction" of the latter's infrastructure.

It also said it would target the regional assets of any Israeli ally that got involved.

South Korean President Yoon Suk Yeol met with his national security and economic advisers on Wednesday over the Middle East conflict and called for a swift but measured response to any impact on the country's energy supply, his office said.