Explosions have erupted in the Lebanese capital Beirut after Israel threatened "imminent strikes" on Hezbollah's financial sites.
The Israeli Defence Forces (IDF) said on Sunday evening it was planning to attack a "large number" of locations used by the group's al Qard al Hassan unit, which is used to pay its operatives and help buy arms.
The first warnings affected southern Beirut and the eastern Bekaa valley but according to a senior Israeli intelligence official, strikes are likely "all over Lebanon". One was seen near the city's Rafic Al Hariri International Airport.
Images released by the IDF - and verified by Sky News - show a building collapsing after being hit by an Israeli strike.
This same building was one of a number identified by Israeli forces as a target just hours earlier.
IDF spokesman Daniel Hagari warned civilians: "Anyone who will be near the sites used to finance Hezbollah's terrorist activity is required to stay away from them immediately."
It came just hours after Israel claimed it struck Hezbollah's intelligence quarters in Beirut.
"The IAF (Israeli Air Force) conducted an intelligence-based strike on a command centre of Hezbollah's intelligence headquarters and an underground weapons workshop in Beirut," the IDF said earlier on Sunday.
"Additionally, the IAF... struck and eliminated the terrorist Al-Haj Abbas Salama in the area of Tebnine, a senior commander in Hezbollah's southern front, and terrorists Rada Abbas Awada and Ahmad Ali Hussein."
The IDF claimed it took "numerous steps" to "mitigate the risk of harming civilians" in both instances.
In response 160 rockets were fired over the Lebanese border into the north of Israel over the course of Sunday, the Israeli military added.
There have been tensions at the border - between the Israeli military and Iranian-backed Hezbollah forces - since the 7 October Hamas attacks last year.
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The conflict escalated earlier this month when Iran sent missiles directly into Israel, with the region still awaiting Israel's response.
US officials are now investigating a possible leak of two top-secret intelligence documents around Israel's response.
According to Sky's partner network NBC News, the alleged leak revealed US intelligence agencies tracking possible retaliation options by Israel.
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Separately over the weekend, the Lebanese army said three of its soldiers were killed by Israeli strikes in the south of the country.
The army is not affiliated with Hezbollah, which is considered a proscribed terrorist group by most Western nations.
Israel did not comment on the reports but has previously said its fight is with Hezbollah - and not the Lebanese state - despite repeated skirmishes between the two sets of soldiers at the border over the past year.
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Sunday also saw UN forces in Lebanon accuse Israel of "deliberately demolishing" an observation tower and perimeter fence of one of its positions in the border town of Marwahin.
It warned: "Yet again, we remind the IDF and all actors of their obligations to ensure the safety and security of UN personnel and property and to respect the inviolability of UN premises at all times."
'At least 87' killed in single Gaza attack
Meanwhile in Gaza, at least 87 people are reported to have been killed in one of the deadliest attacks on the territory in months, according to Hamas-run health authorities there.
The airstrikes on the northern town of Beit Lahiya late on Saturday also left 40 others injured, the Hamas-controlled Gaza health ministry said.
Beit Lahiya was one of the first parts of Gaza to be targeted following the 7 October massacre last year.
Israel disputed the figures when they first emerged, which increased from 10 to 60, 73, and then 87. The Gaza health ministry does not differentiate between civilians and Hamas fighters in its death and injury numbers.
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Israel 'switching objectives' in Gaza
The assault on Beit Lahiya comes around two weeks on from a major strike nearby in Jabalia - home to one of Gaza's largest refugee camps.
The IDF says it has ordered people to evacuate the area and the rest of Gaza's north - including staff and patients in hospitals where it claims Hamas fighters are hiding - something the group denies.
More than 5,000 people have now left Jabalia via formal routes but hospital medics are refusing to heed evacuation orders there - with many warning they are designed so Israel can control northern Gaza when the current conflict ends. Israel denies this and claims to be trying to protect civilians.
According to Sky's military analyst Sean Bell, Israel's renewed focus on the north of Gaza - where it began its campaign in 2023 - suggests it has "switched its objectives" to "destroying Hamas's ability to fight entirely".