Turkey's president has declared a state of emergency for three months following Friday night's failed army coup.

Speaking at the presidential palace in Ankara, Recep Tayyip Erdogan vowed that "all the viruses within the armed forces will be cleansed".

The declaration could be used to extend the detention of nearly 10,000 people rounded up since the failed coup.

More than 600 schools have been closed and thousands of state workers sacked in a crackdown by the president.

"This measure is in no way against democracy, the law and freedoms," said Mr Erdogan after announcing the state of emergency.

He praised those who were killed fighting against the coup as "martyrs". Some 246 people were killed resisting the attempted coup, according to the government.

Mr Erdogan was speaking after holding meetings of Turkey's national security council and the cabinet in the capital.

German Foreign Minister Frank-Walter Steinmeier responded to Mr Erdogan's speech by urging the Turkish government to maintain both the rule of law and a sense of proportionality in its response to the coup attempt.

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

"It's also critical that the declaration of emergency be the truly necessary length of time, and to end the measure as quickly as possible."

The president has blamed the coup attempt on US-based cleric Fethullah Gulen, a former ally whose followers run a worldwide network of schools.

He has called for Mr Gulen to be extradited to Turkey, but US Secretary of State John Kerry said on Wednesday that Turkey must provide hard evidence the cleric was behind the coup attempt for any extradition to take place.

Earlier, Mr Erdogan warned of further arrests and suspensions to come as Turkish authorities continued to pursue those they believed responsible for the thwarted putsch.

More than 50,000 state employees have been rounded up, sacked or suspended in the days since the coup attempt. On Wednesday, 99 top military officers were charged in connection with the events of the weekend.

Officials continued to take action against university and school employees, shutting down educational establishments, banning foreign travel for academics and forcing university heads of faculty to resign.

The government has also revoked the press credentials of 34 journalists who it alleges are connected to Mr Gulen, according to Turkish media.

Amnesty International described the authorities' actions as "a crackdown of exceptional proportions".