LONDON — The editor of the Daily Mirror, the main tabloid rival to Rupert Murdoch's market-leading Sun, told an inquiry Monday that phone hacking might have also happened at his paper.

Richard Wallace told the Leveson Inquiry into the culture, practices and ethics of the press that any hacking at the Daily Mirror would have happened without his knowledge.

Prime Minister David Cameron set up the inquiry following the phone-hacking scandal which led to the closure of Murdoch's weekly tabloid, the News of the World, in July.

When asked by counsel to the inquiry, David Barr, if he was aware of hacking at the Daily Mirror, Wallace, who has edited the paper since 2004, replied "not to my knowledge".

But when asked if it might have occurred without his knowledge Wallace replied: "It might well have."

Wallace added that it was "possible" a story about an affair between the then England football manager Sven-Goran Eriksson and a TV show host, Ulrika Jonsson, in 2002 may have come from voicemail interception.

The Daily Mirror has always previously denied any illegal activity relating to phone-hacking.

The paper's former editor Piers Morgan, who is now a chat show host on US news channel CNN, said he did not believe phone hacking went on at the Daily Mirror when he appeared at the inquiry in December.

Morgan quit as editor of the Daily Mirror in 2004 amid a scandal over faked pictures of British troops abusing Iraqis.