JERUSALEM (AP) - An international cyber attack campaign against Israeli government websites on Sunday failed to cause serious disruptions despite dire threats from the Anonymous hacker collective, Israeli officials said on Sunday.

The global hacker group promised a mass assault to protest Israeli policy toward the Palestinians. The attack appeared timed to coincide with Israel's annual Holocaust memorial day, beginning at sundown on Sunday.

The cyber attack was just the latest in an almost constant effort by Israel's enemies and ideological opponents to shut down its vital websites.

Most of the attacks have had little impact, and Israeli experts even say they welcome the attempts as ways of sharpening their defences. Israel itself is accused of taking part in much more sophisticated cyber attacks against its enemies, particularly Iran.

Web posters using the name of the hacking group Anonymous warned they would launch a mass attack on Israeli sites in a strike they called (hash)OpIsrael, starting April 7.

An official from the militant Palestinian Hamas, which rules the Gaza Strip, praised the attackers. "God bless the minds and the efforts of the soldiers of the electronic battle," Ihab Al-Ghussein, Gaza's chief government spokesman, wrote on his official Facebook page.

By late afternoon, though, few disruptions had been reported.

The Foreign Ministry's website was taken down for a few seconds, but no other ministries behind the government firewall were affected, said Ram Alfia, an official at the Finance Ministry, which oversees the government's websites. He said some slowdowns in local Internet service were expected because of government countermeasures.

Israel is considered one of the world's cyber powers. Its secretive high-tech military units have helped turn the country into a leader in cyber security, and Prime Minister Benjamin Netanyahu has identified cyber security as a top priority.