Waves of strikes pounded Hezbollah's south Beirut stronghold on Tuesday in the most intense raids on the area in two months of full-scale war with Israel — a sign it was aiming to inflict punishment on Hezbollah down to the last moments before any ceasefire takes hold.

Plumes of smoke also rose over Beirut as an Israeli strike targeted a residential building in the center of the capital, without prior warning.

An Israeli strike on a Beirut building housing displaced people on Tuesday, killed at least three people, as raids formed "a belt of fire" around the capital's southern suburbs.

The strike levelled a building in the densely-populated area of Basta al-Fawqa, without a prior warning, the second strike in recent days in the crowded area near the city's downtown.

Britain on Tuesday called for an end to the fighting between Israel and Hezbollah, insisting that a ceasefire was "the only way to restore security" for civilians in Lebanon and northern Israel.

"We urge all parties to engage in efforts to reach a ceasefire and indeed a long-term sustainable peace in the Middle East," Prime Minister Keir Starmer's spokesman told reporters.

The Israeli military said Tuesday its ground troops have reached parts of Lebanon’s Litani River — a focal point of the emerging ceasefire.

In a statement Tuesday, the army said it had reached the Wadi Slouqi area in southern Lebanon and clashed with Hezbollah forces.

Lebanon’s caretaker Foreign Minister Abdallah Bou Habib said Tuesday he hoped a ceasefire to end fighting between Israel and Hezbollah would be agreed later on Tuesday.

Israel's Defense Minister Israel Katz told the U.N.'s Lebanon envoy on Tuesday that any breach of a ceasefire deal that the security cabinet is set to vote on would result in Israel acting "forcefully".

"If you do not act, we will do it, forcefully," Katz told envoy Janine Hennis-Plasschaert when meeting her in Tel Aviv, adding Israel would have "zero tolerance" when defending its security interests in the future, according to a statement from his office.

Residents of northern Israel – many of whom have been displaced by the conflict with Hezbollah, along with residents of southern Lebanon across the border – have expressed concern about the looming ceasefire deal.

A senior Israeli officer has resigned following the deaths of two people, including a 70-year-old Israeli man, in a Hezbollah ambush last week in southern Lebanon.

The Israeli military has launched an investigation into last Wednesday’s incident, in which 70-year-old Zeev Erlich was killed along with a 20-year-old soldier.

The U.N. rights chief is gravely concerned over the escalating conflict between Israel and Hezbollah in Lebanon and wants a "permanent ceasefire" there and in war-ravaged Gaza, his spokesman said Tuesday.

"The only way to end the suffering of people on all sides is a permanent and immediate ceasefire on all fronts: in Lebanon, in Israel and in Gaza," Jeremy Laurence, a spokesman for Volker Turk, told reporters in Geneva.

Israeli warplanes struck buildings in Beirut's suburbs and in the southern city of Tyre Tuesday, as Israel's security Cabinet prepared to vote on a U.S.-brokered ceasefire proposal aimed at ending more than a year of fighting with Hezbollah.

The Israeli army issued airstrike warnings for more than 17 buildings in Haret Hreik, Hadath, Burj al-Barajneh and Ghobeiri.