Jerusalem (AFP) - Israel said Tuesday it was ready to counter any attack from Iran as a US official warned of an imminent missile strike, after Israeli raids against Tehran-backed militants in Lebanon sent tensions soaring.

The Israeli ground offensive across the country’s northern border came despite growing calls for de-escalation after a week of air strikes that killed hundreds in Lebanon, including Hassan Nasrallah, the powerful leader of Iran-backed militant group Hezbollah.

A senior White House official told AFP that “the United States has indications that Iran is preparing to imminently launch a ballistic missile attack against Israel”.

The Israeli military said it had not detected any “aerial threat” from Iran “for now” but stood ready to “defend and attack”.

Defence Minister Yoav Gallant discussed the “imminent” Iran threat with Pentagon chief Lloyd Austin, a statement from his office said.

While Iran-backed groups like Hezbollah had already been drawn into the Gaza war, sparked by Palestinian group Hamas’s October 7 attack on Israel, Tehran has largely refrained from direct attacks on its regional foe.

Early Tuesday, the Israeli military said troops had started “targeted ground raids” in south Lebanon, across Israel’s northern border, though officials have provided few details of the scale of the operation or its timeframe.

The UN peacekeeping mission in Lebanon said the Israeli offensive did not amount to a “ground incursion” and Hezbollah denied any troops had crossed the border.

A Lebanese army source told AFP the force had “not observed any penetration by Israeli enemy forces”.

There was no way to immediately verify the claims, which came as Israel struck south Beirut, Damascus and Gaza, despite international calls for restraint to avoid a regional conflagration.

“We fear a large-scale ground invasion by Israel into Lebanon would only result in greater suffering,” said UN human rights office spokeswoman Liz Throssell.

- ‘Cease hostilities’ -

Israel’s defence minister warned the fight was far from over, even after a massive strike on Beirut killed Nasrallah on Friday.

Israel seeks to dismantle Hezbollah’s military capabilities and restore security to the north, where tens of thousands have been displaced by nearly a year of cross-border fire.

The Israeli military said its forces, backed by air strikes and shelling, carried out “limited, localised, targeted operations” in Lebanon.

To “enable the continuation of operational activity” against Hezbollah, the military later announced it was calling up four additional brigades to the border.

The Iran-backed group, which suffered heavy losses in a spate of attacks last month, said it targeted an Israeli intelligence base near Tel Aviv and other military facilities on Tuesday, as air raid sirens sounded and blasts rang out in the coastal city.

World leaders called for de-escalation after Israel announced the launch of its ground operation.

China said it opposed “infringements on Lebanon’s sovereignty”, while Russia said it “calls on the Israeli authorities to immediately cease hostilities”.

Austin gave Washington’s backing to Israel “dismantling attack infrastructure along the border”, though President Joe Biden had earlier said he opposed a ground invasion.

“We should have a ceasefire now,” said Biden, whose government is Israel’s top arms provider.

- ‘Sacrifice’ -

Hezbollah began low intensity strikes on Israeli troops a day after its Palestinian ally Hamas staged its unprecedented attack on Israel on October 7, which triggered Israel’s devastating assault on Gaza.

Iran has said Nasrallah’s killing would bring about Israel’s “destruction”, though the foreign ministry said Monday that Tehran would not deploy any troops to confront Israel.

The White House official said Washington was “actively supporting defensive preparations to defend Israel against” the potential Iranian attack.

The Pentagon said the United States was boosting its forces in the Middle East by a “few thousand” troops.

German airline Lufthansa has extended its suspension of flights to Beirut and Tel Aviv, citing “the current situation in the Middle East”, with Dutch airline KLM following suit.

Lebanon’s official National News Agency said an Israeli air strike on Ain al-Helweh Palestinian refugee camp killed six people, and Israeli shelling of border communities killed 10.

Elsewhere, Syria’s state television said anchor Safaa Ahmad was killed “in the Israeli aggression” on Damascus, and official news agency SANA reported three civilians killed.

Lebanon’s Health Minister Firass Abiad said more than 1,000 people have been killed since September 17.

Lebanese Prime Minister Najib Mikati and the UN humanitarian agency appealed for more than $400 million in aid for the displaced, estimating there could be as many as one million.

In central Beirut, Youssef Amir, displaced from southern Lebanon, said: “I have lost my home and relatives in this war, but all of that is a sacrifice for Lebanon, for Hezbollah”.

Beirut resident Elie Jabour, 27, told AFP that despite opposing Hezbollah “politically… I support them defending the border”.

Some Israelis welcomed the news of a ground offensive in Lebanon.

Troops should “clean up the area and bring peace”, said 60-year-old firefighter Yossi Cohen, a resident of the northern city of Haifa.

“If they don’t do it this time… our children won’t be able to live here.”

- Gaza strikes -

In Gaza, the civil defence authority said Israeli bombing killed 12 people on Tuesday in the central Nuseirat refugee camp.

Seven others were killed in Israeli strikes on a school sheltering displaced people east of Gaza City.

Hamas’s October 7 attack on Israel resulted in the deaths of 1,205 people, mostly civilians, according to an AFP tally based on Israeli official figures that include hostages killed in captivity.

Israel’s retaliatory military offensive has killed at least 41,638 people in Gaza, most of them civilians, according to figures provided by the Hamas-run territory’s health ministry. The UN has described the figures as reliable.

Hamas appealed for “global solidarity with Gaza and Lebanon” in rallies planned for the war’s first anniversary on Monday.

burs/ami/kir