Manchester United have reported ref Manuel Grafe to UEFA.

The Daily Star says the German official took charge of United's 4-0 win against Feyenoord in the Europa League at Old Trafford on Thursday.

But before the match, Grafe objected to being searched on his arrival.

This is standard procedure, with clubs on high alert because of the risk of a terrorist attack.

United officials were stunned at Grafe's refusal to co-operate.

The referee, 43, later apologised but United had already made a complaint.