A day after a suspected Israeli attack killed Hamas' vice president in a Hezbollah stronghold in Beirut, UN peacekeeping forces in Lebanon issued a warning on Wednesday that escalating hostilities might prove "devastating".

"We are deeply concerned at any potential for escalation that could have devastating consequences for people on both sides," said UNIFIL deputy spokeswoman Kandice Ardiel.

"We continue to implore all parties cease their fire, and any interlocutors with influence to urge restraint."

Saleh al-Aruri, the vice president of Hamas, was killed in a hit on Tuesday in the southern suburbs of Beirut, two Lebanese security officials told AFP, accusing Israel.

After nearly three months of fighting Israel in Gaza, Hamas has acknowledged Aruri's death, which Lebanese state media stated was caused by an Israeli drone strike that also claimed the lives of six other people.

Aruri will be laid to rest on Thursday in the Shatila Palestinian refugee camp near Beirut, according to Hamas.

The nearly three-month-old war saw an increase in violence following the attack.