Cables show concern that Erdogan has been shifting allegiance from the west to Muslim countries like Iran [EPA]

Recep Erdogan, Turkey's prime minister, has accused US diplomats of spreading "slander" and "gossip" after hundreds of thousands of secret US embassy cables were leaked earlier this week.

"The unserious cables of American diplomats, formed from gossip, magazines, allegations and slander are spreading worldwide via the Internet," Erdogan told NTV, the Turkish news channel, on Sunday.

The whistle-blower website Wikileaks posted the trove of confidential, often negative messages about world leaders, including some that depicted Erdogan as a corrupt leader and portrayed him as an "Islamist".

The diplomatic messages at times show concerns that Turkey, a candidate for European Union membership, is shifting its allegiances from western countries towards Iran and other Muslim countries, since Erdogan took office in 2002.

The cables also portray Erdogan as an authoritarian, distrustful leader of his ruling AK Party and say that he believes God appointed him to lead Turkey.

A 2004-dated cable leak quoted Eric Edelman, the then-US ambassador to Turkey, as saying: "We have heard from two contacts that Erdogan has eight accounts in Swiss banks.

"His explanations that his wealth comes from the wedding presents guests gave his son and that a Turkish businessman is paying the educational expenses of all four Erdogan children in the US purely altruistically are lame," Edelman said.

'Propaganda'

Erdogan has denied he has any money in Swiss bank accounts and threatened to file a lawsuit over the charges.

The Turkish leader also suggested the release of the trove of cables may be "propaganda" aimed at damaging relations between the United States and its allies.

"Are there disclosures of state secrets, or is there another aim? Or is it an operation in which certain documents, within a clear timetable, are filtered through a censor?," he said.

"Is it carrying out a veiled, dark propaganda? Are there efforts to affect, manipulate relations between certain countries?"