Media baron Rupert Murdoch says he is humbled by the phone-hacking scandal engulfing his British press operations but adds he is not personally responsible for it.

The 80-year-old Murdoch answered questions before a Parliament investigative committee on Tuesday alongside his son James, his chief deputy at his global media company, News Corporation. The elder Murdoch called his first-ever testimony before Parliament “the most humble day of my life.”

But when asked whether he was personally responsible “for this fiasco,” he tersely replied, “No.”

Asked who was, Murdoch laid the blame on “people that I trusted to run it, and then maybe the people they trusted.”

Both father and son answered questions for more than two hours. But the hearing was halted briefly when one person in the hearing room rushed the table where they were sitting in what appeared to be an attempt to attack the elder Murdoch with a plate of shaving cream. His wife, Wendi Deng, who was sitting behind him, jumped up and swung her right hand at the attacker to protect her husband and security forces quickly subdued the attacker.

In their testimony, the Murdochs repeatedly apologized for the phone-hacking of several thousand calls by journalists they employed at the News of the World tabloid they shut recently after 168 years of publication. The elder Murdoch said he was “absolutely shocked, appalled and ashamed” when he learned two weeks ago that one reporter at the tabloid had hacked into the cellphone of murdered schoolgirl Milly Dowler.

One non-Murdoch London newspaper has suggested that some Murdoch employees tried to hack into the cellphones of victims of the 2001 terrorist attacks against the United States. But Murdoch said his company has seen “no evidence” that it occurred and did not believe that U.S. Federal Bureau of Investigation has found any either in the first stages of its investigation.

Murdoch said he “cannot believe that it happened to anyone in America.”

The younger Murdoch told the legislative panel that he and his father had “great regret” about the phone-hacking and said the conduct did not “live up to the standards” of their News Corporation. He said they were determined to “put things right.”

Both Murdochs said they have been surprised at the scope of the wrongdoing and often said they had been unaware of various details until they were exposed by limited investigations their executives and police had conducted.

At one point, when asked about one of the journalists who has been arrested, the elder Murdoch replied gruffly, “Never heard of him.” He noted that one explanation for the “laxity” of his knowledge was that the News of the World accounted for less than 1 percent of his company's worldwide operations.

He said he only learned after the fact that the company had paid out big amounts to settle lawsuits brought against the company by phone-hacking victims, $1.1 million in one case.

The elder Murdoch's car was mobbed by photographers as he arrived more than two hours ahead of his testimony. Lawmakers were already sharply questioning London police officials about their close connections with former editors and journalists at Murdoch's British operations, including the News of the World.

Paul Stephenson, who quit Sunday as London police chief, testified that he regretted hiring Neil Wallis, a former editor at the tabloid, as a public relations consultant for the police agency known worldwide as Scotland Yard. The 60-year-old Wallis was arrested last week on suspicion of conspiring to intercept communications.

The former police chief called it an “embarrassing contract” with Wallis but said he had “no reason” to connect him to the phone-hacking allegations when he was hired. Stephenson also said he was “unlucky” to find out that Wallis had a business connection to the health spa that he stayed at for free while recovering from surgery.

Stephenson said that 10 of the 45 staff members in the police agency's media and public relations department formerly worked for the News of the World.

His testimony came as British Prime Minister David Cameron cut short a trip to Africa to attend an emergency session of Parliament and to try to contain the crisis. His appointment records show that he has met or socialized 26 times with Murdoch and his executives since he became the country's leader 15 months ago.

News of the World reporters have been accused of illegally accessing thousands of cellphone voice mails of celebrities, politicians, rival journalists and even murder victims.

The scandal has led to the resignations of London's top two police officers, Stephenson and John Yates. Rebekah Brooks, who has resigned as head of Murdoch's British operations, and Mr. Cameron's former communications chief, Andy Coulson – another former News of the World editor – have been arrested.

British reporter Sean Hoare, who first revealed the phone-hacking scandal, was found dead Monday. Britain's Press Association news agency reports police say the death is not considered suspicious.

The New York Times had quoted Hoare as saying phone hacking was widely used and encouraged at the tabloid under Coulson.

In the United States, the Federal Bureau of Investigation has begun a probe into whether employees of Murdoch's media conglomerate tried to hack into the phones of September 11 terrorist attack victims and their families or tried to bribe police for information.

Murdoch's company owns several U.S. news and entertainment outlets, including the country's top business newspaper, The Wall Street Journal, and a major television outlet, Fox News Channel.