London's Metropolitan Police Service has begun looking into the Daily Mail, Daily Mirror and possibly other newspapers, a police data-protection officer told CNN.
The Mail and Mirror had no immediate comment.
Former Mirror editor Piers Morgan, who now hosts CNN's "Piers Morgan Tonight," denied ever engaging in phone hacking, either at the Mirror or earlier, when he was at the News of the World.
"In my time at the Mirror and the News of the World, I have never hacked a phone, told anybody to hack a phone or published any story based on the hacking of a phone," Morgan said on CNN.
News Corp. executive James Murdoch, son of Chairman and Chief Executive Officer Rupert Murdoch, was accused Thursday of misleading if not lying to the parliamentary committee that questioned him about the hacking scandal. Two former News of the World senior executives claimed the evidence the younger Murdoch gave to the committee Tuesday -- about a payment to the head of the England and Wales soccer association, whose phone was hacked -- was "mistaken."
Colin Myler, News of the World editor until the newspaper was shut down almost two weeks ago, and Tom Crone, the tabloid's former head of legal affairs, said they expressly told James Murdoch of an e-mail that made clear it was not only one "rogue reporter" involved in the phone-hacking scandal, The Guardian reported.
This contradicts what James Murdoch told the committee when he was questioned Tuesday.
News Corp. had no immediate comment.
Separately, News Corp.'s Fox News Channel, a CNN competitor, was accused by a former Fox News employee, a producer identified as Dan Cooper, of having a "brain room" that carried out "counterintelligence" on the Fox cable channel's perceived enemies from its New York headquarters, The Daily Telegraph reported.
"These allegations are completely false," a Fox News Channel spokeswoman said Thursday. "Dan Cooper was terminated six weeks after the launch of the Fox News Channel and has peddled these lies for the past 15 years."
A former Fox senior executive said the channel, owned by the Fox Entertainment Group, a News Corp. subsidiary, spied on staff members, reading their e-mails and making them "feel they were being watched," the Telegraph said.
The channel -- which has come under pressure amid allegations Murdoch outlets might have hacked or tried to hack the voicemail messages of Sept. 11, 2001, victims -- denied the allegations.
The News of the World phone-hacking scandal forced the tabloid to close, prompted two top Scotland Yard police officials to resign and put pressure on British Prime Minister David Cameron, who hired a former News of the World editor to be his spokesman.