GESHER HAZIV, Israel (AFP) – Explosions were heard near Israel’s border with Lebanon on Thursday, witnesses and AFP correspondents said, as Lebanese security sources said militants had fired four rockets at Israel.

Witnesses reported hearing several blasts near the northern coastal town of Nahariya.

The Israeli army said that none of the rockets had hit the ground inside Israel.

But an AFP correspondent reported a hole in the ground in Gesher Haziv, a kibbutz east of Nahariya, with debris causing damage to two cars and a number of homes nearby.

“We heard about four or five explosions, and then the sirens went off for about a minute,” a woman named Yasmin from the northern village of Klil told AFP.

The emergency services said no injuries were reported.

A security source in Lebanon said four rockets were fired at Israel from the south.

“Unknown gunmen fired four rockets from two positions, south and east of Tyre, at Israel,” the source said as residents in the area said they heard four blasts.

The Israeli army said its Iron Dome missile defense system intercepted one of “three or four rockets fired from south of Tyre.”

The interception took place between Nahariya and the coastal town of Acre, further south.

None of the rockets, which were “probably a launching done by a global jihadi organization,” hit Israeli territory, army spokesman Lieutenant Colonel Peter Lerner told journalists, saying they might have fallen “in the sea or elsewhere.”

Lerner added that airspace in the north of Israel had been closed following what he described as an “unprovoked attack on Israeli citizens.”

The Israeli army did not retaliate, Lerner said, and another spokesman said the army considered the attack an “isolated incident.”

But Israeli Prime Minister Benjamin Netanyahu warned of future retaliation.

“Anyone who harms us, or tries to harm us, should know — we will strike them,” he said in a televised address.

Arieh Herzog, a former director of the Israeli defence ministry’s Missile Defence Organisation, warned “this kind of attack could [provoke] very serious action from our side.”

He stressed, however, that missile defence capabilities were “much better” than they had been during Israel’s 2006 war against Lebanese Shiite movement Hezbollah.

“We don’t have enough [Iron Dome] batteries… to cover each and every city in Israel,” he told reporters.

“But there’s been a big change since the second Lebanon war. At that time, many rockets fell on the northern part of Israel. Our defences are much better today than in the past.”

The Iron Dome batteries, which are deployed throughout Israel, can shoot down rockets with a range of up to 70 kilometres (44 miles).

Israeli police urged residents of the north to remain close to bomb shelters after Thursday’s rocket fire.

It was the first such incident since November 2011, when an obscure Al-Qaeda-linked group calling itself the Abdullah Azzam Brigades fired a volley of rockets from southern Lebanon at Israel, provoking a reaction from the Israeli army.

The same group had claimed responsibility for a rocket attack in 2009.