File photo: The Anonymous hackers collective has vowed to unleash waves of cyberattacks on Islamic State after the Paris terror attacks.

Tel Aviv - Pro-Palestinian activists on Monday staged a series of cyber attacks against Israeli websites, but experts said no serious damage was caused.

The attack, carried out on the anniversary of a similar event which took place last year, was organised by global activist group Anonymous under the hashtag #OpIsrael.

Several websites were affected in the latest attack, the most significant of which was the site of the Department of Education.

The others were less prominent sites whose homepage was defaced. “It seems that the extent of today's attack was less than that of the past attacks,” said Erez Kreiner, head of cyber defence at Five C, an Israeli security consultancy.

Previous attacks included blocking web traffic and the publication of users' passwords and other sensitive information from websites including a currency trading platform.

“This attack posed no high level security threat to the state or to the economy. At least not what has been visible so far today,” Kreiner said.

He warned, however, that the hackers group was very competent and appeared capable of conducting more serious attacks in the future.

In part, the damage was minimised by security officials taking precautions ahead of the attack, after the group publicised it on internet forums.

“We live in an age when a cyber attack can happen at anytime. We have to always be prepared and have safeguards in place,” said Kreiner. - Sapa-dpa