Turkish authorities on Tuesday arrested 55 senior police officers in a criminal probe over alleged corruption and abuse of office, the latest apparent crackdown on opponents of Prime Minister Recep Tayyip Erdogan ahead of presidential polls.
Forty serving and former top police officers were arrested in Istanbul, including the former head of the anti-terrorism unit of Istanbul police, Omer Kose, television reports said.
Fifteen others were arrested elsewhere, in what the reports said was a new sweep against the movement of Erdogan's former ally Fethullah Gulen in the wake of a vast corruption scandal implicating the prime minister and his inner circle.
In the huge operation conducted in the early morning, police in Istanbul alone raided almost 200 addresses.
Television pictures showed the senior police officers being led outside in handcuffs with some raising their handcuffed hands above their heads in a show of defiance.
The Hurriyet daily said on its website that simultaneous raids were conducted in 22 cities across Turkey.
The suspects are accused of espionage, illegal wire-tapping, forgery in official documents, violation of privacy, fabricating evidence, and violation of secrecy of investigation, the reports said.
Istanbul's prosecutor's office said in a statement that the head of Turkey's National Intelligence Organisation (MIT) Hakan Fidan was among the key figures who were wiretapped.
Erdogan has accused supporters of Gulen of holding excessive influence in the country's police and judiciary and concocting a graft scandal to unseat his government ahead of March local polls.
Erdogan's Islamic-rooted Justice and Development Party (AKP) scored a decisive victory in those local polls, and the prime minister is now standing in elections for president to be held on August 10.
After 11 years in power which has seen his government tame the influence of the once-powerful military, Erdogan has declared a war against Gulen, accusing him of running a "parallel state".
In a television interview late Monday, Erdogan bitterly vowed that the fight against the Gulen movement would continue "non-stop" while calling on the United States to extradite the exiled cleric from his base in Pennsylvania.
"I expect the United States to take a stance on the Gulen issue," Erdogan said.
Erdogan has faced the worst crisis of his over decade-long rule after allegations that he and his allies engaged in corruption which ranged from bribery to gold smuggling and illicit trade with Iran.
His Islamic-leaning government has already sacked thousands of police and prosecutors believed to be linked to the movement in the wake of the scandal and tightened controls over the judiciary and the Internet.
Erdogan and Gulen were once close allies who transformed the political landscape of Turkey, which for decades was ruled by secular governments closely watched over by coup-happy generals.
Gulenists, said to number in the millions and known for their piety and business acumen, say their faith seeks to merge a "civil Islam" with modernity, science and Turkish nationalism.
Gulen, who left for the US in 1999 to escape charges of anti-secular activities by the government of the time, has denied being behind the graft allegations against Erdogan.