Turkey on Tuesday dismissed over 15,000 state employees and ordered the closure of 375 associations within the state of emergency imposed after the July failed coup, in a purge that shows no sign of slowing.

More than 100,000 people have already been suspended or sacked so far in a crackdown on those alleged to have links to coup-plotters while dozens of media outlets have been shut down.

In the latest government decree published on Tuesday, 7,586 personnel working in the police, including police chiefs and commissioners, were dismissed.

Meanwhile 1,956 soldiers and personnel in the air force and navy were sacked while another 403 were removed from the gendarmerie, which looks after domestic security.

Thousands more were dismissed in government ministries and state institutions, including nearly 3,000 officials in the interior ministry and related institutions.

In total, 15,726 people have been dismissed under the latest decrees.

The dismissals are permitted under the state of emergency, which was extended by another three months in October, and was originally imposed in the wake of the coup.

But its scope has been vehemently criticised by the European Union and human rights activists.

- 'Silence critical voices' -

The decrees, published in the latest issue of the official gazette, also ordered the closure of 375 associations across the country working on issues ranging from rights to culture to women.

Critics have claimed that the crackdown goes well beyond the suspected coup plotters and targets anyone who has dared show opposition to President Recep Tayyip Erdogan.

"The closure of nearly 400 NGOs is part of an ongoing and systematic attempt by the Turkish authorities to permanently silence all critical voices," said Amnesty International's Europe Director, John Dalhuisen.

Amnesty said the groups closed included lawyers associations working on preventing torture, women's rights groups working against domestic violence and local NGOs helping refugees.

Among those ordered closed is the leading Ankara-based children's rights NGO Gundem Cocuk (The Agenda is Children).

The decrees also ordered the closure of nine provincial press outlets and 19 health institutions.

Ankara blames the coup plot on the US-based Muslim preacher Fethullah Gulen and says an unrelenting campaign is needed to root out his influence from public life. Gulen denies the allegations.

Erdogan indicated in a speech on Tuesday that the purges would continue, saying that not all Gulen supporters had been rooted out of Turkish institutions.

"We know that the state has not been entirely cleared of this treacherous network.

"They are still in our armed forces, our police organisations, inside our judiciary, inside different state institutions," he said.

In a separate development on Tuesday, Turkish authorities detained 20 staff at Silivri jail outside Istanbul accused of using the Bylock messaging app that Ankara says was specially developed by Gulen supporters for the coup plot.

Those detained include the head of the prison, named as H.T., it added. Hundreds of suspects rounded up after the coup are being held in the jail.