ISTANBUL (REUTERS) - Turkey suspended thousands of police officers on Monday (July 18), widening a purge of the armed forces and judiciary after a failed military coup, and raising concern among European allies that it was abandoning the rule of law.

A senior security official told Reuters 8,000 police officers, including in the capital Ankara and the biggest city Istanbul, had been removed from their posts on suspicion of links to Friday's coup bid by a faction in the army.

Thirty regional governors and more than 50 high-ranking civil servants have also been dismissed, CNN Turk said.

Thousands of members of the armed forces, from foot soldiers to commanders, were rounded up on Sunday, some shown in photographs stripped to their underpants and handcuffed on the floors of police buses and a sports hall. Several thousand prosecutors and judges have also been removed.

More than 290 people were killed and around 1,400 wounded in the violence on Friday night, as soldiers commandeered tanks, attack helicopters and fighter jets in a bid to seize power, strafing parliament and the intelligence headquarters and trying to seize the main airport and bridges in Istanbul.

President Tayyip Erdogan on Sunday told crowds of supporters, called to the streets by the government and by mosques across the country, that parliament must consider their demands to apply the death penalty for the plotters. "We cannot ignore this demand," he told a chanting crowd outside his house in Istanbul late on Sunday. "In democracies, whatever the people say has to happen."

He called on Turks to stay on the streets until Friday, and late into Sunday night his supporters thronged squares and streets, honking horns and waving flags.

The bloodshed shocked the nation of almost 80 million, where the army last used force to stage a successful coup more than 30 years ago, and shattered fragile confidence in the stability of a Nato member state already rocked by Islamic State in Iraq and Syria (ISIS) suicide bombings and an insurgency by Kurdish militants.

EU foreign policy chief Federica Mogherini warned the Turkish government on Monday against taking steps that would damage the constitutional order.

"We were the first... during that tragic night to say that the legitimate institutions needed to be protected," she told reporters on arrival at an EU foreign ministers meeting, which was also to be attended by US Secretary of State John Kerry. "We are the ones saying today rule of law has to be protected in the country," she said in Brussels. "There is no excuse for any steps that take the country away from that."

Austrian Foreign Minister Sebastian Kurz said it would be unacceptable for Turkey to reintroduce the death penalty, which it abolished in 2004. Abolishing capital punishment was a prerequisite for talks with Turkey on membership of the European Union, to which it still aspires.

Turkey's pro-Kurdish HDP opposition, parliament's third largest party, said it would not support any government proposal to reintroduce the death penalty. The main CHP opposition said the response to the coup attempt must be conducted within the rule of law and that the plotters should face trial.

"HEAVY BLOW" TO MILITARY

Turkish security forces are still searching for some of the soldiers involved in the coup bid in various cities and rural areas but there is no risk of a renewed bid to seize power, a senior security official told Reuters.

The official said Turkey's military command had been dealt "a heavy blow in terms of organisation" but was still functioning in coordination with the intelligence agency, police and the government. Some high-ranking military officials involved in the plot have fled abroad, he said.

Erdogan has blamed US-based Muslim cleric Fethullah Gulen for orchestrating the attempted power grab. He has long accused the cleric of trying to create a "parallel state" within the courts, police, armed forces and media.

Gulen, in turn, has said the coup attempt may have been staged, casting it as an excuse for Erdogan to forge ahead with his purge of the cleric's supporters from state institutions.

The swift rounding up of judges and others indicated the government had prepared a list beforehand, the EU commissioner dealing with Turkey's membership bid, Johannes Hahn, said. "I'm very concerned. It is exactly what we feared," he said in Brussels.

A Turkish official acknowledged that Gulen's followers in the armed forces had been under investigation for some time, but denied that an arrest list had been prepared in advance. "In our assessment, this group acted out of a sense of emergency when they realized that they were under investigation. There was a list of people who were suspected of conspiring to stage a coup," the official said. "There was no arrest list. There was a list of people suspected of planning a coup."