Germany has complained to Russia about a series of raids on nongovernmental organizations, including two German think tanks.
A Foreign Ministry official says Foreign Minister Guido Westerwelle "invited" the second-in-rank diplomat at Russia's Berlin embassy to express "concern over the concerted action" by Russian law-enforcement authorities.
German media quoted a diplomat as saying that "hindering the activity of German foundations could inflict lasting damage on bilateral relations."
The Konrad Adenauer Foundation and the Friedrich Ebert Foundation are among more than 100 Russian and Western NGOs that have been submitted to similar inspections in recent days.
Authorities said the inspections are aimed at determining whether the groups are in compliance with Russian law.
Activists see the inspections as a crackdown.
Based on reporting by Reuters, AFP, and spiegel.de