Murdoch, whose News Corporation empire includes HarperCollins publishers, Fox television, BSkyB, The Wall Street Journal and the London Times, wrote Saturday on Twitter: "Why is Jewish owned press so consistently anti-Israel in every crisis?"

Facing accusations of anti-Semitism, Murdoch backtracked on Sunday, saying he disagreed with his critics, but was sorry anyway.

"'Jewish owned press' have been sternly criticised, suggesting link to Jewish reporters. Don't see this, but apologize unreservedly," Murdoch, who is known as a strong Israel supporter, said in a new tweet.

On yesterday, Murdoch apologised again, this time to the Jewish Anti-Defamation League, saying he had simply been upset by media coverage of Israel's intensive bombing campaign in response to rockets fired out of Palestinian Gaza by Hamas.

"I feel very strongly about the righteousness of Israeli's cause, particularly when its citizens are under missile attack. So I do get very upset when I see coverage that I feel is unfair and biased," he said in a letter to the ADL. "I should have stuck to the substance of the issue and not bring in irrelevant and incorrect ethnic matters."

Britain's Guardian newspaper said Murdoch was "trying to channel the right wing's ardent support of Israel by challenging the left wing's more critical view of Israeli brinksmanship -- particularly as Israel appears on the verge of another invasion of Gaza."

CNN's media commentator weighed in, saying Murdoch's tweet "went beyond outrageous to offensive, truly offensive. He played off the worst kind of historical libel against Jews.