HAMILTON, Canada

UN Secretary-General Antonio Guterres denounced the escalation of conflict in Lebanon as Israel has been pounding the country with airstrikes for more than one week.

"The Secretary-General is extremely concerned with the escalation of the conflict in Lebanon," according to a statement by spokesperson Stephane Dujarric.

Urging for an immediate cease-fire, Guterres warned against "an all-out war" and said it must be avoided in Lebanon at all costs.

"The sovereignty and territorial integrity of Lebanon must be respected," he added.

Guterres had a telephone call with Lebanese Prime Minister Najib Mikati early Tuesday in which he ensured that "the entire United Nations system in Lebanon is mobilized to assist all those in need in the country."

"The Secretary-General appeals to the international community to urgently support the $426 million humanitarian appeal launched today in Beirut," said Dujarric.

The statement emphasized Guterres' commitment to continue talks, and pledged that UN staff on the ground would "continue their efforts to de-escalate the situation."

Israel launched massive airstrikes since Sept. 23 against what it calls Hezbollah targets across Lebanon that have killed more than 1,057 victims and injured north of 2,950, according to the Lebanese Health Ministry.

Several leaders of the Lebanese resistance group have been killed in the strikes, including leader Hassan Nasrallah.

Hezbollah and Israel have been engaged in cross-border warfare since the start of Israel's onslaught against the Gaza Strip, which has killed nearly 41,600 victims, most of them women and children, following a cross-border attack by the Palestinian resistance group, Hamas, last October.

The international community has warned that Israeli attacks in Lebanon could escalate the Gaza conflict into a wider regional war.