The new wave of arrests targeted 18 police figures, including the former head of national police intelligence, Omer Altiparmak, and the former deputy head of the Ankara police, Lokman Kircili.

The operation is the fifth swoop in a sequence of coordinated raids against police since July. So far, dozens of former senior officers have been arrested.

It was not immediately clear if all those targeted figures had been arrested, but Turkish media said that the operation was still underway.

The swoops were part of a crackdown on what the Turkish president has described as a “parallel state” within the security forces loyal to his former ally-turned-foe, Fethullah Gulen.

The probe is linked to corruption allegations against the president and cabinet ministers.

More than 100 serving and former police officers were arrested in July as part of a wiretapping investigation.

The officers have been accused of fabricating a probe as cover for spying on top figures since 2010, including Erdogan, cabinet members and the head of Turkey’s National Intelligence Organization, Hakan Fidan.

Many of the police officers arrested were involved in an anti-government corruption probe and were removed from their posts earlier this year.

Turkey plunged into political crisis after dozens of government officials and prominent businessmen close to the Turkish premier were arrested for inquiry on graft charges on December 17, 2013.

Erdogan denounced the corruption scandal as well as a string of damaging leaks in the media, saying they were engineered by Gulen’s supporters to undermine his government. Gulen has repeatedly denied any involvement.