A flurry of diplomatic activity is underway to contain an expected Israeli response against Hezbollah, Lebanon's top diplomat said, after an attack blamed on the group killed civilians in the annexed Golan Heights.

On Sunday, Israeli Defense Minister Yoav Gallant had vowed to "hit the enemy hard" after rocket fire killed 12 minors, raisings fears the war in Gaza could spread.

Airlines suspended flights to Lebanon on Monday as diplomatic efforts were underway to contain soaring tensions between Hezbollah and Israel after deadly rocket fire in the annexed Golan Heights.

Several airlines including Lufthansa, Air France and Transavia announced Monday the suspension of their Beirut lines.

Monday saw a flurry of diplomatic activity, as caretaker Prime Minister Najib Mikati held "intensive diplomatic contacts," including a call with British Foreign Secretary David Lammy, who “renewed the call on all parties to exercise restraint to prevent escalation,” Mikati’s office said in a statement.

Lammy posted on social media site X that he had called Mikati “to express my concern at escalating tension and welcomed the Government of Lebanon’s statement urging for cessation of all violence.”

Lebanon has called for an international investigation into a strike that killed 12 people including children on the Israeli-annexed Golan Heights, warning against a large-scale retaliation.

The Israeli military said that an Iranian-made rocket that Lebanon's Hezbollah group fired on Saturday hit a football field in Majdal Shams, a Druze Arab town, killing children and teenagers who were playing there.

U.N. Secretary-General Antonio Guterres has condemned a strike that killed 12 young people in the Israeli-annexed Golan Heights.

Calling on all parties to "exercise maximum restraint," Guterres sent his "deepest condolences to the families of those who lost their lives" while adding that "civilians, and children in particular, should not continue to bear the burden of the horrific violence plaguing the region," according to a statement by the office of his spokesperson.

Lebanon's Middle East Airlines said in a statement that it had rescheduled a number of flights on Sunday and Monday, citing "technical reasons related to the distribution of (aircraft) insurance risks".

In October, the carrier said it was relocating some planes abroad in light of regional developments.

Hezbollah has evacuated positions in south and east Lebanon after Israeli threats of reprisals for a deadly strike on the annexed Golan Heights, a source close to the group said.

Israeli Defense Minister Yoav Gallant vowed to "hit the enemy hard" a day after rocket fire from Lebanon killed 12 minors in Majdal Shams, again raisings fears that the war in Gaza will spread.

The White House has said that rocket fire that killed 12 young people in the Israeli-annexed Golan Heights was "conducted by Lebanese Hezbollah."

Calling the attack "horrific," National Security Council Spokeswoman Adrienne Watson said in a statement Sunday that "it was their rocket, and launched from an area they control. It should be universally condemned."

A strike that killed 12 young people in Majdal Shams in the Israeli-annexed Golan Heights, has prompted Israeli Prime Minister Benjamin Netanyahu to return early from the United States.

Israel blamed Lebanon's Hezbollah for firing a Falaq-1 Iranian rocket but the Iran-backed group said it had "no connection" to the incident.

Israel has blamed Lebanon's Hezbollah for a strike that killed 12 young people in Majdal Shams in the Israeli-annexed Golan Heights.

Hezbollah said it had "no connection" to the incident.