Turkey appoints trustee mayors to 24 municipalities on grounds that previous mayors provided support to "terrorists".

Turkey has removed 24 mayors accused of links to Kurdish separatist fighters, replacing them with state-appointed trustees in a major shake-up under emergency powers enacted after a failed coup attempt.

The mayors were suspended from their posts over the past month on suspicion of links to the Kurdistan Workers' Party (PKK), a group that has been waging a deadly insurgency in the southeast since 1984, an interior ministry statement said.

Another four mayors were removed on suspicion of links to the US-based cleric Fethullah Gulen, a former ally of President Recep Tayyip Erdogan who is now blamed for the July 15 failed coup attempt.

All 28 mayors were replaced on Sunday with state-appointed trustees.

While most of the removed mayors belonged to pro-Kurdish parties, three of them were from the ruling Justice and Development Party (AKP) and one was from the opposition Nationalist Movement Party (MHP).

Mayors from the AKP and MHP are accused of having links to Gulen movement, according to Turkish media.

The move is the most largest step yet taken by new Interior Minister Suleyman Soylu since he took over from Efkan Ala in a surprise reshuffle earlier this month.

Soylu said the move meant that local municipalities would no longer be controlled by "terrorists or those under instructions from Qandil", referring to the PKK's mountain base in northern Iraq.

The move was made within the three-month state of emergency imposed after July's coup attempt. The incumbents had all been elected in 2014 local polls.

The municipalities affected, mainly in the southeast, include important, predominantly Kurdish urban areas such as Sur and Silvan in the province of Diyarbakir and Nusaybin in the province of Mardin.

The mayors of the cities of Batman and Hakkari in the southeast have also been replaced. The interior ministry said 12 of the mayors suspended are already under arrest.

The pro-Kurdish Peoples' Democratic Party (HDP), whose regional politicians were the among the chief targets of the move, denounced the reshuffle as a "coup". 

In a statement, the HDP said the move was reminiscent of the military takeover in 1980 and "ignored the will of the voters".

"The government should immediately abandon this perilous step," it said, "they should quit trying to take advantage of the recent coup attempt on July 15th."

But Justice Minister Bekir Bozdag denied the authorities had ridden roughshod over democracy, accusing the suspended mayors of funnelling revenues to "terror" groups.

"Being elected does not grant a right to commit a crime," he wrote on Twitter.

Elsewhere, Turkish media reported that the police dispersed crowds that had gathered to protest the new mayoral assignments in southeastern provinces, and short clashes erupted in several areas.

Security forces in Hakkari prevented HDP co-mayors Fatma Yildiz and Saban Alkan from entering the municipality building following Sunday's assignments, which led to protests outside the municipality building.

Police dispersed the crowd after they refused to leave the scene, the Turkish daily Hurriyet reported.

Four people, including Deputy Mayor Mikayil Erdal and HDP district organisation head Asim Ozcan, were detained but released shortly after, newspaper said.

In Batman, another group from the HDP gathered to protest the assignments to four municipalities in the province. Police fired tear gas and used water cannons to disperse the crowd.

In addition, around 200 people also protested the assignments in the Suruc district of the southeastern province of Sanliurfa.

The US Embassy in Ankara said on Sunday that it was concerned by reports of clashes in southeastern Turkey.

"We are concerned by reports of clashes in Turkey's southeast following the government's decision to remove some elected local officials from office on charges of supporting terrorism, and appoint local trustees in their place," the embassy said in a statement posted on Twitter.

It said it supported Turkey's right to defend itself against terrorism but noted the importance of respect for due process and the right to peaceful protest.

"We hope that any appointment of trustees will be temporary and that local citizens will soon be permitted to choose new local officials in accordance with Turkish law," it said.

The Turkish military said on Wednesday that 186 PKK members had been killed in the operations conducted in the southeastern district of Cukurca over the past few days.

A total of 11,285 personnel "linked to a separatist-terrorist organisation have been suspended," Turkey's education ministry said on its official Twitter account on Thursday.

Turkey, the US and the EU have branded the PKK a "terrorist organisation".

The autonomy-seeking group abandoned a two-year ceasefire in July, reigniting a conflict that has claimed more than 40,000 lives since 1984.

The government has accused the PKK of a series of attacks in the southeast of Turkey in recent weeks.