Police say a mosque and an international congress center were attacked in two explosions in the German city of Dresden, but that nobody was injured.

Dresden police said in a statement Tuesday the explosions took place late Monday, and there was no immediate report on the extent of damage.

Police President Horst Kretschmar says that "even though we do not have a letter of confession, we must assume there's a xenophobic background."

Police say they found pieces of a home-made explosive device in front of the congress center. They also increased the security in front of mosques all over Dresden.

Dresden will hold Germany's national unification celebrations next Monday. It's the state capital of Saxony which has seen a lot of racist attacks recently.