Police estimated that about 3,000 protesters gathered in Munich and marched through the city's centre, while in Frankfurt, between 1,000 and 1,300 demonstrated.

The cities are home to large Turkish communities, part the 2.4 million people of Turkish origin who live in Germany.

Last month, 18 police officers were injured after violence broke out between Kurds and nationalist Turks during a protest in Berlin.

Turkey has threatened military action against PKK bases in northern Iraq and has accused the Iraqi Kurds there of tolerating and aiding the PKK.

Tensions along the Turkish-Iraqi border increased after October 21, when PKK militants ambushed a military unit, killing 12 soldiers and capturing eight. The captives have since been released.

The PKK, listed as a terrorist group by Ankara and much of the international community, has waged a 23-year armed campign for Kurdish self-rule in Turkey's southeast. The conflict has claimed more than 37,000 lives.