LONDON — Labour challenged Prime Minister David Cameron on Sunday to "come clean" over his links with the Murdoch media empire, reviving pressure on the government over phone hacking.

In letters to Cameron and senior ministers, Labour asks dozens of questions about the premier's decision to hire Andy Coulson, a former editor at the now defunct News of the World, and about Rupert Murdoch's takeover bid for BSkyB.

Coulson quit as Cameron's media chief in January and was arrested this month for alleged phone hacking and police bribery, which he denies. Cameron defended his appointment, but admitted that with hindsight, he would not have hired him.

The government has also come under fire for its meetings with Murdoch and his executives while the media tycoon's News Corp was bidding to take over pay-TV giant BSkyB. It abandoned the offer this month.

The pressure on Cameron has eased this week, but as lawmakers begin their summer recess, Labour -- which has been at the forefront of the charge against Murdoch -- is stepping it up again.

Labour lawmakers have written to Cameron, Chancellor of the Exchequer George Osborne and others demanding "they come clean", a party spokesman said.

"David Cameron and George Osborne treated warnings about Andy Coulson with contempt and failed to put a proper distance between themselves and senior News Corp executives during the consideration of the BSkyB bid," said Ivan Lewis, Labour's Shadow Culture, Media and Sport Secretary.

He said there were "serious doubts" about their judgment, saying they had behaved in "a cavalier and reckless way".

"A tangled web of their own making will not go away until they and their cabinet colleagues give full and frank answers to legitimate questions," he said.

Earlier this month, Cameron and his ministers published a list of their meetings with senior media figures dating back to the election in May 2010, and they have promised to do this regularly from now on.

"I think we have been pretty clear, we are taking action," a Downing Street spokeswoman told AFP.

However, Labour wants details of what was discussed with News Corp executives about BSkyB, and on how Coulson was hired, including whether it was on the advice of News Corp executives or whether anyone raised any concerns.