Murdoch launches paper to replace disgraced tabloid

London (CNN) -- Rupert Murdoch launched a new British tabloid Sunday to replace his disgraced News of the World, seven months after the best-selling Sunday paper was shut down over a phone-hacking and bribery scandal.

The "new" newspaper isn't entirely new -- it's a Sunday edition of Murdoch's Sun tabloid, which had been a six-day-a-week paper until now.

Its leading editorial on launch day took a defensive tone in discussing the closure of the News of the World.

"The Sun has been a tremendous force for good," its editors insisted. "It is worth reminding our readers, and detractors, of that as we publish our historic first Sunday edition."

Tension high at "The Sun" newspaper

The parent company of both tabloids, News International, "closed our sister paper the News of the World over the phone hacking scandal. Since then some of our own journalists have been arrested, though not charged, over allegations of payments to public officials for stories," the editors said.

"We believe those individuals are innocent until proven guilty," they said.

The first edition of the Sunday tabloid sets a tone like that of its weekday sister, leading with the story of a television presenter's difficult childbirth and putting a scantily-clad picture of singer Kelly Rowland on page three -- a slot occupied by topless models during the week.

Nelson Mandela's hospitalization at the age of 93 makes page 8, under the headline "Nelson Tum Op" and above a picture of actress Kate Winslet in a low-cut dress accepting an acting prize.

Under Murdoch, News of the World specialized in undercover investigations and salacious stories that earned it the nickname "News of the Screws."

But revelations last year that it had paid for the hacking of voice mail messages to murder and terrorism victims and fallen troops, as well as celebrities and politicians, forced the paper to close.

Police are running three separate investigations -- into phone hacking, e-mail hacking, and police bribery -- and two parliamentary committees and an independent inquiry are also probing British press practices.

Murdoch testified before one of the panels of lawmakers last year, calling it the "most humble day of his life."

A former spokesman for Prime Minister David Cameron, ex-News of the World editor Andy Coulson, is among those arrested. No one has been charged.

The Sunday Sun launched with a print run of 3 million, far more than any daily newspaper sells in Britain, but well below the 4.75 million sales for the last issue of News of the World, according to its publisher.

News of the World was 168 years old and among the best-selling newspapers in the world when it closed.