Mark Lewis said a "well-known sports person," a non-public sports person and a U.S. citizen were affected by the phone-hacking of the defunct British publication, News of the World, the BBC reported Thursday.
"The News of the World had thousands of people they hacked. Some of them were in America at the time, either traveling or resident there," he said.
The publication's owner, News International, declined to comment.
Lewis, who declined to name his clients, said the scandal "is not just then confined to the United Kingdom or to the United Kingdom companies like News International and News Group Newspapers."
"This goes to the heartland of News Corporation and we'll be looking at the involvement of the parent company in terms of claims there and that is something that will be taken more seriously by perhaps the investors and shareholders in News Corporation," Lewis told the BBC.
He said none of his three clients would be considered high profile, but could be considered "collateral damage" because they may have received or left messages during the time of the hacking.
Lewis said he's been contacted by other British lawyers about more potential U.S. cases.
The phone-hacking first came to light in 2006 when the tabloid's then-Royal Editor Clive Goodman and private investigator Glenn Mulcaire were accused of illegally tapping into voice mails of royal aides. They drew jail terms of four months and seven months, respectively.
News of the World was closed in July 2011 after evidence came to light that the practice was more widespread. Several newspaper executives and journalists were arrested.
At least 50 claims against the defunct publication have been settled. Police said more than 4,000 people were identified as possible victims.
The matter is subject of several investigations by police and an inquiry by Parliament.