* Erdogan locked in power struggle with U.S.-based Muslim cleric
* Blames cleric for leaked audio recordings on Internet
* In latest leak, PM purportedly urges sacking of reporters
By Daren Butler and Humeyra Pamuk
ISTANBUL, March 7 (Reuters) - Prime Minister Tayyip Erdogan has threatened to ban Facebook and YouTube in Turkey in an attempt to stop political foes anonymously posting audio recordings purportedly exposing corruption and other malpractices in his inner circle.
In the latest recording, released on YouTube late Thursday, Erdogan is purportedly heard berating a newspaper owner over the telephone about an article and suggesting the journalists be sacked, in comments that will further stoke concerns over media freedom and Erdogan's authoritarian style of leadership.
Erdogan, who rejects any accusations of corruption, blames U.S.-based Turkish Muslim preacher Fethullah Gulen, a former ally, for the wiretaps which he says have been "fabricated". Gulen, who denies any involvement, has many followers in Turkey, especially in the police and judiciary.
"We are determined on this subject. We will not leave this nation at the mercy of YouTube and Facebook," Erdogan said in an interview with Turkish broadcaster ATV aired late on Thursday.
"We will take the necessary steps in the strongest way," he said, adding that these would come after municipal elections in Turkey set for March 30.
Asked if a ban on these sites could be included among the planned measures, he said: "Included, because these people or institutions encourage every kind of immorality and espionage for their own ends."
There was no immediate reaction from Facebook or YouTube.
Turkey banned YouTube for more than two years until 2010 after users posted videos the government deemed insulting to the republic's founder, Mustafa Kemal Ataturk.
Turkey's communications minister appeared to defend the putative bans.
"We see insults against a country's prime minister and president, the uploading of illegal videos - and we're supposed to be at ease with this? ... Whatever is a crime in the real world is also a crime in the virtual world," the Dogan news agency quoted Lutfu Elvan as saying on Friday.
Turkey recently tightened government control of the Internet saying it wanted to defend privacy. Erdogan's critics said the new law was a further bid to hush up allegations of high-level graft flooding social media and video sharing sites.
Erdogan says the postings are part of a campaign to discredit him and wreck his government, which has presided over more than a decade of strong economic growth and rising living standards in NATO-member Turkey.
He says fragments of tapped conversations have been fitted together in a 'montage' giving a false and misleading impression of their content.
Five more recordings have appeared on YouTube this week alone, part of what Erdogan sees as a campaign to sully his ruling Islamist-rooted AK Party before the March 30 local elections and a presidential poll due later this year.
Reuters has not been able to verify the authenticity of the recordings.
In Thursday's audio posting, Erdogan is portrayed taking to task businessman Erdogan Demiroren after his newspaper Milliyet published on its front page about a year ago an article on the sensitive issue of peace talks with Turkey's Kurdish rebels.
"Would you keep someone who would do something dishonourable in your office, would you keep them there for another hour?" the voice presented by the anonymous poster as that of the prime minister asks.
"No, we wouldn't," replies Demiroren, who later in the conversation bursts into tears, apparently upset at coming under pressure from the prime minister to sack two of his journalists.
The AK Party, which remains far ahead of its rivals in opinion polls despite the corruption scandal, denies exerting undue influence over the media, but journalists, rights groups and the European Union - which Turkey aspires to join - have long accused the government of curtailing press freedoms.
In another recording this week, Erdogan purportedly urges his then-justice minister to speed up a court case against a media magnate who belongs to a secular elite which has often had tense relations with the Islamist-rooted government.
A Turkish official told Reuters that data and logs related to digital recordings from before 2012 had been deleted in the database of Turkey's state telecommunications authority TIB.
It was not clear what had happened to the recordings but pro-government media reports said they had been copied and deleted by Gulen's followers.
Statistics and information from before 2011 on how many people had been listened to had also been deleted. The official said this made it impossible to produce evidence for court cases related to those recordings.
According to figures he provided, some 250,000 people were wiretapped in 2011, 583,000 in 2012 and 607,000 in 2013.