Lebanese Prime Minister Nawaf Salam denounced on Saturday what he called a dangerous Israeli escalation in the south, urging an immediate ceasefire and insisting that a "scorched-earth policy" would not ensure Israel's security.

In a televised address, Salam also defended his government's direct negotiations with Israel -- which Iran-backed Hezbollah opposes -- saying that the talks were the "least costly path" for Lebanon.

"In light of the dangerous and unprecedented Israeli escalation over the past few days, it is necessary to step up political and diplomatic efforts to achieve a swift and real ceasefire," Salam said.

He accused Israel of "pursuing a scorched-earth policy and collective punishment" by "destroying towns and villages, and forcing their inhabitants into exile". 

This will bring "neither security nor stability" to Israel, he said.

Salam's broadcast came after Israel's military issued new evacuation warnings for residents of more south Lebanon villages, and a day after military delegations from both countries held landmark security talks in Washington.

Those talks took place ahead of US-brokered negotiations early next week -- the fourth round since the latest Israel-Hezbollah conflict erupted in March.

Salam said the outcome of the direct negotiations with Israel was "not guaranteed", but that they "are the least costly path for our country and our people".

A US statement after Friday's talks made no mention of a ceasefire, and Israel has recently intensified its air and ground operations against Hezbollah.

A truce to halt the fighting officially took effect on April 17, but has never been observed.

© Agence France-Presse