Turkey's Prime Minister Recep Tayyip Erdogan has stated that the graft operation of the Istanbul Prosecutor's Office was a coup attempt by the judiciary in the country.

He claims he is the victim of a conspiracy that is threatening Turkey's "future and stability" and has launched a harsh attack on the magistrates over the inquiry into bribery and corruption within the government.

Speaking at a luncheon to 45 prominent members of the Turkish media, pro-government intellectuals, and writers at the government residence Dolmabahce in Istanbul, Erdogan said: "In this process, there has been in Turkey an attempt to seize the sovereignty from the people and transfer it to the judiciary."

Erdogan expressed confidence that Turkey would overcome its current difficulties. He pointed to municipal elections set for March as a test for the regime in upcoming presidential elections in August.

"We will not allow a cloud to be cast over Turkey's future," he said.

Meanwhile Turkish President Abdullah Gul has promised that any corruption would not be hushed up, saying that "if acts of corruption are covered up, society will disintegrate."

A number of well-known people in Turkey, including prominent businessmen and the sons of three ministers were arrested on December 17 on suspicions of bribes in construction projects and illegal money wires to Iran.

Erdogan replaced 10 ministers, but the scandal has put a serious dent in his power and came close to his family as well. His son Bilal Erdogan is also under investigation for "establishing and belonging to a criminal organization for gain."

Erdogan has repeatedly said he believes he is the real target of the probe, behind which he sees a scenario for the overthrow of power in Turkey. He has hinted that the attack came from supporters of an influential Turkish Muslim cleric Fethullah Gulen, who lives in the US.

At the luncheon, the PM also claimed he has received a letter of reconciliation from Gulen.

Gulen's followers see him as a more progressive and pro-Western influence than Erdogan, whose opinions on issues from abortion to alcohol consumption, and the concentration of power around him they view with increasing alarm.

The corruption investigation poses the biggest challenge to Erdogan in his 11 years as leader.

The scandal has affected the economy with the Turkish lira plummeting to a new record low of 2.1765 against the dollar, bringing its losses since the launch of the probe to almost 6%, although the central bank has increased support for the country's currency.

The turmoil on the markets has been accompanied by mass street protests demanding Erdogan's resignation.