Turkish President Abdullah Gul, who is on a four-day visit to Germany, has canceled a speech at one of Berlin's universities after an anonymous bomb threat.
Police evacuated the lecture hall at Humboldt University and cordoned off the capital's main Unter den Linden boulevard outside the building. Several hundred Kurds had gathered outside to demonstrate for the release of Abdullah Ocalan, the leader of the Kurdistan Workers' Party (PKK).
The PKK is listed as a terrorist group by Ankara and much of the international community. Earlier in the day, Gul held talks in Berlin with his German counterpart, Christian Wulff.
Turkey is a candidate for the European Union, but its accession has been opposed by German Chancellor Angela Merkel, who said it should be granted a "privileged partnership" over full membership.
Gul and Merkel were scheduled to hold talks on September 20.
compiled from agency reports