(CNN) -- Several Israeli government websites appeared to crash as anti-Israeli hackers launched cyberattacks Sunday, but Israeli hackers also claimed their own victory.
The website that promoted the "OpIsrael" cyberattacks was itself hacked. Instead of anti-Israeli messages, it was playing Israel's national anthem, "Hatikvah."
A group calling itself Anonymous Arab said in a YouTube video posted last week its cyberattack plan would come in three phases.
"Step one will be initiated after the release of this message and will be comprised of systematically removing the Zionist entity from the Internet," a speaker said in Arabic. The video shows a masked person appearing to read.
"Step two, we will discover your future plans and show your crimes against humanity to the whole world," the speaker said. ""And as for step three, well think of this one as a present from Anonymous to you."
It concluded: "We are Anonymous. We are legion. We do not forgive. Expect us."
The websites for Israel's Knesset and elections agency appeared to be down Sunday.
Yitzhak Ben Yisrael, the head of the Israel's National Cyber Directorate, downplayed the effects of the cyberattacks in an interview Sunday with Israel Radio.
"As was expected, up until now there has been no real damage, and the hackers don't have the tools to cause damage to the vital infrastructures," Yisrael said.
CNN's Michael Schwarz and Amir Ahmed contributed to this report.