11.   The anniversary is often marred by clashes between anarchists and riot police.

12.   The game was marred by clashes between fans and players at the end of the match.

13.   The match was marred by clashes between hooligans from Salerno and police inside and outside the stadium.

14.   The peace treaty that culminated in the vote has been marred by clashes involving soldiers or demobilized fighters with little to expect in the ruined economy.

15.   The Thursday rally was marred by clashes between police and demonstrators who hurled firebombs, flares and rocks.

16.   Voting on Tuesday was marred by clashes between security forces and opposition supporters that left one person dead and dozens injured.

17.   Such processions have long been marred by clashes between Protestant loyalists and Roman Catholics who favour unification with the Irish Republic.