Seven people have been arrested after 12 police officers were injured during clashes with Legia Warsaw fans at their game against Leicester City.
Leicestershire Police said trouble broke out in the away section during the second half of the Europa League tie at the King Power Stadium.
Flares were let off and some supporters of the Polish club attempted to breach the segregated line, the force added.
Two of the injured officers required hospital treatment.
One of these was for concussion and the other was for a fractured wrist.
The Legia Warsaw fans were held back in the stadium and no further disorder was reported.