Israel has communicated a “stern warning” to Hezbollah through Western and regional intermediaries following the recent assassination of top commander Fouad Shukur that any massive attack on Israeli civilians will lead to war, Israeli sources told the Yedioth Ahronoth newspaper.

“Israel intends to target fighters rather than combat-supporting infrastructure and urges Hezbollah to adopt a similar focus,” the sources added.

Britain’s Foreign Secretary David Lammy and Defense Secretary John Healey arrived Thursday in Beirut following a trip to Qatar.

They met with Speaker Nabih Berri and caretaker Foreign Minister Abdallah Bou Habib following their arrival before heading to the Grand Serail for talks with caretaker Prime Minister Najib Mikati.

By Asher Kaufman, University of Notre Dame

Israel's apparent assassinations of Fouad Shukur, Hezbollah's top military leader, in Beirut, and Hamas political leader Ismail Haniyeh, in Tehran, have raised again the specter of a regional war involving regional adversaries – one that could potentially drag the United States into the fray.

Israel "delivered crushing blows to all our enemies", Prime Minister Benjamin Netanyahu said, explicitly mentioning the killing of Hezbollah leader Fouad Shukur in south Beirut.

Netanyahu's televised statement on Wednesday lasted for approximately five minutes and did not make any reference to the killing of Hamas chief Ismail Haniyeh in Tehran.

An Israeli strike that killed a Hezbollah commander in Beirut and the killing of the political leader of Hamas in Tehran "don't help" regional tensions but there are no signs of an imminent wider conflict, the White House said.

"These reports over the last 24, 48 hours certainly don't help with the temperature going down," National Security Council spokesman John Kirby told reporters Wednesday when asked about the attacks.

Hundreds of mourners on Wednesday chanted "death to Israel" and "America is the Great Satan" at the funeral of two children killed in an Israeli strike on Hezbollah's stronghold in southern Beirut the day before.

The Israeli military said the strike had "eliminated" Fouad Shukur, a top Hezbollah commander it blamed for carrying out a weekend rocket attack on the Israeli-annexed Golan Heights that killed 12 children.

Air France and low-cost carrier Transavia France said Wednesday their flights between Paris and Beirut would remain suspended till the weekend due to the "security situation" in Lebanon.

The two airlines had planned to resume flights on Wednesday, but said they will now remain grounded until Saturday.

Switzerland has urged its nationals to leave Lebanon, noting the highly volatile situation in the country.

Hezbollah confirmed Wednesday that Israel killed a top commander after a rare strike in Beirut.

U.N. Secretary-General Antonio Guterres has denounced strikes on Beirut and Tehran as a "dangerous escalation," after Israel targeted a top Hezbollah commander in Lebanon and Hamas said its political chief was killed in Iran.

"The scretary-general believes that the attacks we have seen in South Beirut and Tehran represent a dangerous escalation at a moment in which all efforts should instead be leading to a ceasefire in Gaza" and "the release of all Israeli hostages," spokesman Stephane Dujarric said in a statement.

The United States has raised its travel advisory on Lebanon to its highest "do not travel" classification, citing rising tensions between Israel and Hezbollah after a strike on southern Beirut killed a top commander of the armed group.

"Do Not Travel to Lebanon due to rising tensions between Hezbollah and Israel. If you are in Lebanon, be prepared to shelter in place should the situation deteriorate," the advisory said Wednesday, adding that citizens in southern Lebanon or in refugee settlements should leave.