Turkish authorities will appoint unelected administrators to run the mainly Kurdish city of Diyarbakir, officials said on Tuesday, after detaining its two mayors last week in a crackdown on unrest in the southeast of the country.

Separately, police detained 30 officials from the opposition Democratic Regions' Party (DBP) in dawn raids in three towns in the restive region, security sources said.

Turkey's Western allies are worried about due process and a deteriorating human rights situation in the southeast as a crackdown against Kurdish militants widens to include politicians and journalists.

President Tayyip Erdogan has vowed to "dry the swamp" to end a three-decade insurgency that has killed more than 40,000 people, mainly Kurds.

The state will name the administrators - who will either be led by the deputy governor or a district official - as soon as possible under powers enacted via decrees during emergency rule, imposed after a failed military coup in July, officials told reporters on condition their names were not used.

"It is expected the Interior Ministry will assign new mayors to the municipality after the mayors were dismissed for terrorism links and arrested," Diyarbakir Governor Huseyin Aksoy said in a statement. All governors in Turkey are appointed.

A prosecutor accuses Gultan Kisanak, Diyarbakir's first female mayor and a former parliamentarian, and her co-mayor Firat Anli of terrorist links in connection with public statements they made about the need for greater autonomy for Kurds, who make up about 20 percent of a population of 79 million people.

Kisanak and Anli, both members of the DBP, deny direct ties with the armed Kurdistan Workers Party (PKK), listed as a terrorist group by Turkey, the United States and European Union.

The EU, to which Turkey has applied for membership, has called the arrests "deeply worrying." But Erdogan has said the removal of elected officials and civil servants accused of links to the PKK is a vital part of the battle against it, as thousands have been killed since the collapse of a ceasefire in 2015.

In October alone, authorities jailed 98 DBP officials, the party said. The DBP dominates the southeast and is the sister party of the Peoples' Democratic Party (HDP), parliament's third-biggest grouping, which has Kurdish roots.

Turkey on Saturday closed 15 newspapers, news agencies and magazines that report from the southeast, bringing the total number of media outlets and publishers closed since the coup to about 160.

The closure of the remaining Kurdish media and the appointment of trustees to run Diyarbakir silences opposition voices and "denies thousands of Kurdish voters their right to local political representation," U.S.-based Human Rights Watch said. Authorities have also blocked the Internet in cities across the region for most of the past week.