German police said they had received a threat of an attack on the Labour Office in the western city of Ludwigshafen, where Turkish Prime Minister Tayyip Erdogan is due to visit later in the day.
"We received a threat," a police spokesman said, adding that dogs were searching the building. He declined to give further details.
On Sunday, a fire in a housing block in Ludwigshafen killed nine people with Turkish backgrounds. Erdogan is due to visit the site later.