German officials on Friday evacuated Gaggenau town’s city hall after it received a bomb threat, Reuters reported. The town’s mayor Michael Pfeiffer told Germany’s N-tv broadcaster that the threat followed his cancellation of an event involving the participation of Turkey’s justice minister.

“We presume this at the moment, but we don’t know for sure. We presume there is a direct link,” Pfeiffer told the broadcaster. “We don’t know how seriously we should take this threat,” Pfeiffer added. City officials had said they had cancelled the event because of limited car parking space, Britain-based Express reported.

Turkish Justice Minister Bekir Bozdag (pictured above) was scheduled to address Turkish President Tayyip Erdogan supporters in a bid to garner support for an upcoming referendum, Express reported. The cancellation of Bozdag’s event and another Turkish rally in Cologne has strained relations between the two countries.

In Ankara, the authorities had summoned Germany’s ambassador to express their disapproval over the event being cancelled. Turkish Foreign Minister Mevlut Cavusoglu had said, “If you want to continue relations, you [Germany] need to learn how to behave towards us. We will respond without hesitation,” Germany’s Deutsche Welle reported.