Israel says the aim of its operations in Lebanon is to allow tens of thousands of its citizens displaced from northern Israel by Hezbollah bombardments to return home safely.

More than 1.2 million Lebanese have been displaced by Israeli attacks, and nearly 2000 people have been killed since the start of the Israeli attacks on Lebanon over the last year, most of them in the past two weeks, Lebanese authorities said.

There are also growing concerns about getting medical supplies for the wounded, and the World Health Organisation said 28 healthcare workers had been killed in Lebanon in the previous 24 hours.

WHO chief Tedros Adhanom Ghebreyesus said flight restrictions meant the agency would not be able to deliver a large planned shipment of trauma and medical supplies to Lebanon on Friday.

Hezbollah says it has repelled several land operations by Israeli troops, including with ambushes and in direct clashes.

Lebanese security sources say Israeli troops have entered Lebanese territory and been pushed back several times in recent days, without setting up a permanent presence.

Rocket sirens wailed constantly in northern Israeli towns, sending residents running for shelter, as Hezbollah kept up its cross-border fire.

The Lebanese army said two soldiers were killed by Israeli strikes in separate incidents in south Lebanon on Thursday, one in an attack on a military post and another in a strike on a rescue mission with the Lebanese Red Cross.

The army said that it returned fire when the military post was struck, a rare development for a force that has historically stayed on the sidelines of major conflict with Israel.

In Beirut’s southern suburb known as Dahiyeh, a dense neighbourhood where Hezbollah holds sway, several explosions were heard on Thursday and large plumes of smoke were rising after heavy Israeli strikes.

Hezbollah said it detonated a bomb against Israeli forces infiltrating a southern Lebanese village and attacked Israeli forces near the border.

Overnight, Israel bombed central Beirut in an attack the Lebanese Health Ministry said killed nine people.

Reuters journalists reported hearing a heavy blast after a building in the district of Bachoura was targeted a few hundred metres from Parliament, the closest an Israeli strike has come to the central downtown district.

A Hezbollah-linked civil defence group said seven of its staff, including two medics, were killed in the Beirut attack.

Israel also said it struck a municipality building in the southern Lebanese town of Bint Jbeil, killing 15 Hezbollah members and destroying many weapons.

As it pushes into Lebanon, Israel is also weighing its options for retaliation against Iran.

Iran launched its largest ever assault on Israel on Tuesday in what it said was retaliation for Israel’s assassination of senior Hamas and Hezbollah leaders and its operations in the Gaza Strip and Lebanon.

Iran said its attack was over, barring further provocation, but Israel has said it will hit back.

The United States has said Iran will face “severe consequences” and that it would work with Israel while warning Iran not to act against US forces in the region.

A number of countries were helping their citizens leave Lebanon.

Iranian President Masoud Pezeshkian, speaking in Doha, said his country would be ready to respond and warned against “silence” in the face of Israel’s “warmongering”.

“Any type of military attack, terrorist act or crossing our red lines will be met with a decisive response by our armed forces,” he said.

Qatar’s Emir Sheikh Tamim bin Hamad Al-Thani called for serious ceasefire efforts to stop what he called Israel’s aggression.