Turkey on Saturday announced the capture of a senior aide to US-based Muslim cleric Fethullah Gulen, who authorities say masterminded the July 15 coup attempt.

A presidential spokesperson said Halis Hanci entered Turkey two days before the coup attempt, adding that he was detained in the Black Sea province of Trabzon.

Authorities also arrested one of Gulen's nephews. But the US-based cleric, an avid critic of the Turkish president, has denied any involvement.

The announcement comes as President Recep Tayyip Erdogan decreed that police could hold suspects for up to a month without charge under new state of emergency powers. The decree also closed over 1,000 schools deemed subversive.

Prime Minister Binali Yildirim also announced Saturday that Turkey will disband the elite presidential guard after detaining almost 300 of its members in the wake of last week's coup attempt. The presidential guard comprises some 2,500 soldiers.

"There will no longer be a presidential guard, there is no purpose, there is no need," the minister told A Haber TV.

At least 270 people were killed during the coup attempt, including 179 civilians, 62 police and five loyalist soldiers.

EU leaders warn Turkey over clampdown

Turkey has witnessed a clampdown on rights since July 15, when a group in the armed forces attempted to overthrow the democratically-elected president.

Over 13,000 people have been detained as suspected enemies of the state, many of them soldiers, police, judges, teachers and civil servants.

Italy's Prime Minister Matteo Renzi has warned Turkey over the mass arrest, saying "a country that jails its own university professors and journalists imprisons its future."

German Foreign Minister Frank-Walter Steinmeier on Thursday called for Erdogan's government to restrain itself in the wake of the failed coup, saying it should end a three-month state of emergency as quickly as possible.

"Only provable involvement in illegal acts, not suspected political leanings, should trigger governmental action," Steinmeier said in a statement.

It is in Turkey's interest to "keep the state of emergency only for the duration that is absolutely necessary and then immediately end it," he added.

ls/cmk (AFP, AP, Reuters, dpa)