Hundreds of Hezbollah rocket launchers that had been set to fire towards Israel have been hit by Israel, in what security sources in Lebanon said on Thursday was the heaviest such attack since hostilities began last October.

Ignited by the Gaza war, the conflict has intensified significantly this week, with Hezbollah suffering an unprecedented attack in which pagers and walkie talkies used by its members exploded, killing 37 people and wounding thousands.

UN peacekeepers in Lebanon urged immediate de-escalation following Israel’s most intense airstrikes in nearly a year of conflict with the Iran-backed Hezbollah.

The UNIFIL peacekeeping force in south Lebanon said on Friday morning that the previous 12 hours had seen “a heavy intensification of the hostilities” across the Lebanese-Israeli border and in its area of operations.

In Gaza, Israeli forces have killed at least 14 Palestinians in tank and air strikes on north and central areas of the Gaza Strip, medics say, as tanks advanced further into northwest Rafah near the border with Egypt.

The unrelenting fighting between the Israelis and Hamas militants in the enclave carried on even as a parallel conflict in the Lebanon-Israel border area involving Hamas’ allies Hezbollah intensified.

And in a new challenge to Palestinians displaced in the Al-Mawasi area in southern Gaza, many were concerned about the danger of high waves. Some tents put up close to the beach flooded last week.

“Enough, enough, enough. We were pushed by the occupation (Israel) to the sea, where we believed it was safe, last week the sea flooded and washed away some tents, and that could happen again, where would we go?” said Shaban, 47, an electrical engineer displaced from Gaza City.

Palestinian health officials said shelling on Friday by Israeli tanks killed eight people and wounded several others in the Nuseirat refugee camp in the central area of Gaza, and six others were killed in an airstrike on a house in Gaza City.

In the northern town of Beit Hanoun, an Israeli strike on a car killed and wounded several Palestinians, medics said.

It was not clear how many of the casualties were combatants and how many were civilians.

In the southern city of Rafah, where the Israeli army has been operating since May, tanks advanced further to the northwest area backed by aircraft, residents said.

In Lebanon, UNIFIL spokesperson Andrea Tenenti told Reuters: “We are concerned at the increased escalation across the Blue Line and urge all actors to immediately de-escalate”, referring to the line that delineates the border between Lebanon and Israel.

Israeli airstrikes on Friday hit at least three villages in south Lebanon, according to security sources in Lebanon and Hezbollah’s al-Manar television, which broadcast footage of a cloud of smoke rising from one of the attacks.

There was no immediate comment from the Israeli military.

The year-long conflict between Israel and Hezbollah is the worst since they fought a war in 2006. Tens of thousands have had to leave homes on both sides of the border.

While the conflict has largely played out in areas at or near the frontier, this week’s escalation has heightened concerns that it could widen and further intensify.

The United States on Thursday warned all parties in the Middle East against escalation, saying Washington’s priority is to find a diplomatic solution.

“We will continue to stand by Israel’s right to defend itself, but we don’t want to see any party escalate this conflict, period,” State Department spokesperson Matthew Miller told a news briefing.

In a TV address on Thursday, Hezbollah leader Sayyed Hassan Nasrallah said the device explosions on Tuesday and Wednesday “crossed all red lines” and vowed to punish Israel.

Israel has not directly commented on the pager and radio detonations, which security sources say were probably carried out by its Mossad spy agency, which has a long history of carrying out sophisticated attacks on foreign soil.

The 15-member Security Council is due to meet on Friday over the blasts.

– with Nidal al-Mugrabi and AAP