Lawmaker John Whittingdale, who heads Parliament's culture, media and sport committee, said it would hold an urgent meeting Thursday on the report by The Guardian newspaper.

"There are a number of questions I would like to put to News International on the basis of what The Guardian has reported," Whittingdale said.

The Guardian reported that the News of the World has paid more than 1 million pounds ($1.6 million) in out-of-courts settlements to some of the targets.

Citing anonymous senior police sources, The Guardian reported that journalists at the tabloid newspaper used private investigators to hack into private voicemail messages, using the information to "gain unlawful access to private data, including tax records, social security files, bank statements and itemized phone bills."

The tabloid's royal editor, Clive Goodman, was jailed for four months in 2007 for hacking into royal officials' voicemail systems. He said he had acted without the knowledge of other journalists or editors.

The newspaper's editor at the time was Andy Coulson, now director of communications for Conservative Party leader David Cameron's. He resigned after Goodman was sentenced but said he had no knowledge of the hacking.

Cameron said he had given Coulson a "second chance" by hiring him after he left the News of the World.

"As director of communications for the Conservatives he does an excellent job in a proper, upright way at all times," Cameron said.

The tabloid is owned by News International Ltd., a subsidiary of Rupert Murdoch's News Corp. The company said in a statement that it would be "inappropriate to comment at this time."

Former Deputy Prime Minister John Prescott, one of the alleged targets, said he had suspected his phone was tapped. He said he wanted to know why he had not been told by police.

He said that "for such a criminal act not to be reported to me, and for action not to be taken against the people who have done it, reflects very badly on the police, and I want to know their answer."

Former Home Secretary Charles Clarke said that the allegations in The Guardian raised serious questions for News International, the Conservatives, and the police.

"I think it is outrageous," he said. "I think we do need action immediately."