DIYARBAKIR, Turkey (Reuters) - Turkish police arrested dozens of Kurdish activists and politicians on Saturday, including a provincial mayor, in their latest push against alleged supporters of armed militants.

Selim Sadak, mayor of Siirt, was among about 60 people detained in simultaneous operations in three southeastern cities, police said. Many are local officials from the legal, pro-Kurdish Peace and Democracy Party (BDP) and civic groups.

Turkey has jailed thousands of Kurdish politicians, academics, lawyers, journalists and others since 2009 on charges they support the Kurdistan Workers Party (PKK), which has fought the state for autonomy in a conflict that has claimed more than 40,000 lives since 1984.

Turkey, the United States and the European Union list the PKK as a terrorist organization.

The BDP said in a statement police operations were continuing.

The latest raids coincide with efforts in the capital Ankara to lift the parliamentary immunity of 10 lawmakers, nine of them from the BDP. This would pave the way to prosecute them, in a move that would weaken Kurdish representation in parliament and may fuel tension in the southeast.

Prime Minister Tayyip Erdogan last week said he favored stripping the Kurdish MPs of their immunity after they were filmed in August embracing armed PKK rebels who had stopped their convoy in the southeast.

Kurdish members of parliament are often under investigation, accused of links to the militants, but are protected from prosecution while they are in office. The BDP denies any outright ties to the PKK.

Erdogan has pledged greater Kurdish political and cultural freedoms since his party came to power in 2002 while applying increasing military pressure on the militants and, occasionally, the BDP, which he calls the PKK's "political extension."

Excluding the latest detentions, some 190 elected BDP officials are already in jail, including 37 mayors. Six BDP lawmakers are also behind bars after they were barred from taking up parliamentary seats they won in 2011.

(Reporting by Seyhmus Cakan and Ayla Jean Yackley; Editing by Mark Trevelyan)