ISTANBUL  -  Turkey has moved to curb the powers of the country’s top independent judicial body, triggering concern Wednesday from Europe’s top human rights watchdog.

The ruling Justice and Development Party (AKP) submitted a bill Tuesday seeking constitutional amendments to restructure the Supreme Board of Judges and Prosecutors (HSYK), the latest twist in the political crisis rocking Turkey.

Justice Minister Beckir Bozdag also said that the government would block an investigation by the HSYK into alleged political pressure on police and prosecutors involved in a graft probe targeting key allies of Prime Minister Recep Tayyip Erdogan.

The moves against the judiciary triggered concern from the Council of Europe’s Commissioner for Human Rights, Nils Muiznieks. “Proposals to curb powers of HSYK represent serious setback for the independence of the judiciary in Turkey,” he said in a tweet. The AKP bill is due to be discussed by a parliamentary commission on Friday, Turkish media reports said.

“In terms of changing the HSYK, we can work with the opposition for a better solution, including a constitutional change. This may include the appointment of members by parliament,” Bozdag said.

The HSYK had said Tuesday it planned to look into allegations that new Istanbul police chief Selami Altinok was blocking prosecutors from carrying out further arrests in the graft probe.

But Bozdag said the government would not allow such a probe into Altinok and Istanbul chief prosecutor Turan Colakkadi, who removed one of the lead investigators in the widening corruption case, Hurriyet newspaper reported.

Others being investigated by the HSYK include prosecutor Muammer Akkas, who was barred last month from expanding the corruption investigation amid reports it may target Erdogan’s son.

Meanwhile, the Turkish government fired 16 provincial police chiefs in a new mass purge Wednesday as a corruption scandal rocking Prime Minister Recep Tayyip Erdogan deepened.

Among those dismissed were police from several big cities and provinces including Ankara, Izmir, Antalya and Diyarbakir as well as the deputy head of national security, under a decree signed by Interior Minister Efkan Ala.

The latest purge comes just a day after the government fired 350 police officers in the capital Ankara - bringing the total number sacked to over 700 since mid-December when the graft scandal broke, according to local media tallies.

Media reports Tuesday also said another 25 people had been detained on suspicion of bribery and fraud in the widening corruption probe that has targeted several key Erdogan allies.

The turmoil has rocked Erdogan’s government to its very core just weeks before crucial local elections in March and has sent Turkish financial markets tumbling. But the government vowed Wednesday it would overcome the crisis.

“The government is in charge. We will never let the political and economic stability of Turkey be disturbed.

We will do our best to prevent this,” Deputy Prime Minister Ali Babacan told private Haberturk television. Battling to contain the biggest threat to his 11 years in power, Erdogan has branded the investigation a “dirty” plot to try to topple his Islamic-rooted government.

He and his allies have blamed supporters of a powerful Muslim cleric who lives in self-imposed exile in the United States but wields considerable influence in Turkey’s judiciary and police.

“It is an attempt to shatter our self-confidence. The attack is not directed against our government, but against Turkey,” Foreign Minister Ahmet Davutoglu said Tuesday. “It is an attempt to create a perception that the entire government is embroiled in massive corruption and that Turkey is passing through a great depression,” he told NTV television.

The crisis erupted in December when dozens of leading businessmen and political figures - including the sons of three ministers - were rounded up in police raids in Istanbul and Ankara.

Erdogan was forced into a major cabinet reshuffle after the three ministers concerned resigned and the government has since gone on the offensive to root out foes in the police and judiciary.

Erdogan’s critics accuse him of desperately trying to protect cronies caught up in the investigation which has focused on alleged bribery in construction projects and illicit money transfers by a state-owned bank to sanctions-hit Iran.

In a new twist to the increasingly complex powerplay, the country’s top judicial body the Supreme Board of Judges and Prosecutors (HSYK) said Tuesday it would investigate allegations that the new Istanbul police chief was blocking prosecutors from carrying out further arrests, as well as alleged misconduct by prosecutors.

Erdogan has vowed to battle what he terms “a state within a state” - an apparent reference to followers of influential Turkish cleric Fethullah Gulen.

The so-called Gulenists - once staunch supporters of Erdogan’s Justice and Development Party (AKP) - hold key positions in various government branches including the police and judiciary.

The crisis has called into question the political future of the prime minister, arguably one of the most powerful figures in modern Turkey who took office after years of government instability and an economic meltdown.

And in his campaign against the Gulenists, he is now seeking to mend fences with the once all-powerful army that he had fought hard to rein in.

He said at the weekend he was willing to see fresh trials for hundreds of military officers jailed in 2012 and 1013 for allegedly plotting coups against his government.

Gulen’s followers were key backers of the AKP when it took office in 2002 but tensions emerged over last year’s anti-government protests and government plans to shut down a network of private schools run by the movement.

Turkey’s financial markets remain jittery, with the Istanbul stock market down slightly on Wednesday while the dollar was at around 2.17 compared to its all time low of 2.19 on Monday.