Britain's deputy prime minister urged Rupert Murdoch Thursday to face questioning by lawmakers over the phone hacking scandal, as pressure grew on his media empire in Australia and the United States.

Police in Britain made a ninth arrest in the case as the furore which has led to the closure of the News of the World tabloid and forced Murdoch to drop a takeover bid for satellite broadcaster BSkyB raged on.

Murdoch, his son James and Rebekah Brooks, the chief executive of Murdoch's British newspaper arm News International faced a deadline Thursday to reply to an invitation by a parliamentary committee to answer questions on the row.

British Deputy Prime Minister Nick Clegg said it was unclear whether they could be forced to appear before MPs, but he said that they should if they wished to be seen as fit and proper proprietors.

"If they have any shred of sense of responsibility, of accountability for their position of power, then they should come and explain themselves before a select committee," Clegg said.

Conservative lawmaker Louise Mensch, a member of the committee, said it may have more powers over Brooks, a British national, than it does over Rupert and James Murdoch, both of whom are US citizens.

"We have powers over British citizens, in other words over Mrs Brooks," Mensch told the BBC, without detailing what those powers were.

"Rupert and James Murdoch are American citizens, we don't have any power over them, but I think it would surprise everybody if they were to have the guts to show up."

There was no immediate reaction from News International. Its only comment on the committee's invitation was to say on Tuesday that it would "cooperate."

The Australian-born Murdoch, 80, has been in London since Sunday struggling to keep his empire afloat after the scandal over mobile phone voicemail hacking at Murdoch's News of the World exploded last week.

The row had rumbled on for months but took on global dimensions after it emerged that it had targeted the messages of Milly Dowler, a murdered 13-year-old girl, and of the bereaved families of soldiers who fought in Afghanistan and Iraq.

Murdoch shut the 168-year-old News of the World on Sunday but that failed to stem the growing criticism of his media empire.

On Wednesday, he announced News Corp. was dropping its bid for full control of BSkyB, whose portfolio includes live English Premier League football and blockbuster films and has 10 million household subscribers.

Officers from Scotland Yard arrested a 60-year-old man at a residential address in London on Thursday "on suspicion of conspiring to intercept communications", the Metropolitan Police said.

It said the man, who was not identified, was in custody at a west London police station.

On Friday police arrested Andy Coulson, a former editor of the paper and the one-time media chief of Prime Minister David Cameron, over phone hacking and allegations of buying off police officers. He was later released on bail.

Cameron told parliament on Wednesday there had been eight arrests so far in the scandal, as he unveiled the details of a full public inquiry.

In Australia, Prime Minister Julia Gillard said on Thursday she would be open to an inquiry into media regulation and ownership after the "disgusting" scandal engulfing News Corp.

"I'm not surprised to see that in parliament or amongst parliamentarians a conversation is starting about the need for a review, and I will be happy to sit down with parliamentarians and discuss that review," Gillard said.

Australia's News Limited, the birthplace of Murdoch's global empire, owns eight of Australia's 12 metropolitan daily newspapers, while Murdoch has extensive Internet assets and a stake in broadcasters Sky News and Fox Sports.

In Washington, Democratic Senators Jay Rockefeller and Barbara Boxer urged US Attorney General Eric Holder and the Wall Street watchdog Securities and Exchange Commission, to launch investigations into the scandal.

The lawmakers cited allegations that Murdoch's news outlets hacked the phones of September 11 victims, saying in a letter that the claims "indicate a pattern of illegal activity, and involve thousands of potential victims."

News Corp's shares have plummeted in the past week, and the Murdoch-owned Wall Street Journal reported that the media tycoon was considering selling off his remaining British newspapers, The Times, The Sunday Times and The Sun.