Two police motorcycles in convoy carrying the British and Belgian prime ministers along a motorway in Belgium were knocked over by a car on Friday in an apparent accident, Belgian media reported.

The two motorcyclists, who were escorting Theresa May and Charles Michel after they laid wreaths at World War One British graves, were taken to hospital. No one else was injured, according to La Libre Belgique newspaper.

De Standaard quoted Belgian premier Michel’s spokesman describing the incident as an “unfortunate accident”.

May was in Belgium to mark Sunday’s centenary of the end of the 1914-18 war and later traveled for further ceremonies in France.