Israeli Defence Minister Moshe Yaalon on Tuesday called for world intelligence agencies to work together against the Islamic State jihadist group.

"In order to stop and overcome the Islamic State, we have learnt since 9/11 that there must be cooperation between intelligence agencies from across the free world, a sharing of experience and operational cooperation," he told public radio.

The Islamic State (IS) has been at the forefront of a sweeping militant assault that has overrun swathes of Iraq, and also has significant areas of territory in neighbouring Syria.

US President Barack Obama on Friday called for a broad coalition to defeat the jihadists, and he is to chair a key UN Security Council session on the threat on September 24.

Asked about the proposed international coalition, former military intelligence chief Amos Yadlin indicated Israel would likely share its intelligence with its allies.

"The intelligence that we gather in the Middle East -- which deals with threats from Iran, (Lebanon's Shiite) Hezbollah, what's happening in Syria, terrorist organisations in Sinai and the Gaza Strip -- is of very good quality and we share it with our allies," he told the radio.

Speaking on condition of anonymity, an official told AFP that Israel was "already cooperating with the relevant authorities in Europe in the fight against the danger posed by radical Islam and its ramifications in Europe."

Foreign ministry spokesman Emmanuel Nahshon said the threat posed by Islamic extremists had already become a reality in Europe.

"The danger represented by organisations like the Islamic State is demonstrated by the attack carried out by a jihadist of French origin against the Jewish Museum in Brussels," he said, referring to a shooting attack in May in which four people were killed.

Suspected gunman Mehdi Nemmouche, a French national of Algerian origin, had "got his experience in terrorism while staying in Iraq and Syria," Nahshon said.

Nemmouche was identified at the weekend as being among a group of Islamic extremists involved in kidnapping and torture in Syria, according to a recently freed French journalist.

Last week, Israel moved to designate both the Islamic State and Al-Qaeda affiliated Abdullah Azzam Brigades as "illegal organisations" under Israeli law, allowing for legal measures to be taken against them as well as against as anyone supporting or financing them.

It came as IS released a video showing the beheading of US journalist Steven Sotloff, who also reportedly held Israeli nationality, in the second such execution of a US journalist within a fortnight.

The Abdullah Azzam Brigades is a Lebanese jihadist group linked to Al-Qaeda which periodically claims rocket fire on Israel.