Turkish police on Wednesday blocked protests over the government's sacking of three mayors in the southeast accused of having links to Kurdish militants, an AFP correspondent said.

At least 200 people attempted to stage a protest march to Diyarbakir's historic Sur district but were met with police water cannons and seven were detained, the correspondent said.

Around 500 officers also surrounded a sit-down protest of 200 people in Diyarbakir.

In all three cases, Ankara-appointed governors were given authority over the cities' administrations.

Van Governor Mehmet Emin Bilmez took the further step of dissolving the municipality's HDP-majority assembly.

The government says the HDP is a political front for the outlawed Kurdistan Workers' Party (PKK), which has waged an insurgency against the Turkish state since 1984.

The HDP denies ties to the PKK, which is on the terror blacklists of Turkey, the United States and the European Union.

The insurgency has claimed more than 40,000 lives.

More than 500 people have been detained in the last three days, including HDP members and supporters protesting against the mayors' removal, a party source told AFP.

Interior Minister Suleyman Soylu played down the protests, saying there was no serious unrest and life was continuing as normal, in remarks to foreign media in Istanbul.

He said the dismissals were necessary to "prevent the abuse of democracy" by people who, he claimed, have used municipal resources to support "terrorists".

"The main problem is the attitude of the HDP which is defying the state by nominating as mayors these people who already face prosecution... They are treating democracy as a Trojan Horse."

The mayors all won large majorities in March local elections.

Separately, the provincial governor of Sirnak, along the borders with Syria and Iraq, said one soldier was killed on Wednesday and three wounded after clashes with the PKK in the district of Silopi.AFP