Germany is banning defense contractor Rheinmetall from shipping some products to Turkey.
"The German government is currently denying clearance for some export contracts", Rheinmetall Chief Executive Armin Papperger told reporters on Thursday after the release of its full-year results.
He said Rheinmetall remained in talks with Turkey over a contract to supply a defense system for its Leopard battle tanks, after the country lost 10 such vehicles in its war against the Islamic State.
Rheinmetall and peer Krauss Maffei jointly build the Leopard tanks, Reuters reports.
The decision comes after a row over campaign appearances by Turkish officials to drum up support for a referendum, which will be held on April 16.