KIEV, June 28 – In a move that may have serious diplomatic consequences, Ukraine’s SBU security service on Saturday stopped and tried to deport a Western analyst belonging to an influential German think tank.

Niko Lange, who has led the Konrad Adenauer Foundation’s Kiev office for the past three years, was stopped at Boryspil airport after the authorities denied him entry to Ukraine.

The attempt to block the entry by Lange comes at a sensitive time, as Ukraine’s foreign ministry has been working on organizing a visit by Yanukovych to Germany in August.