Demonstrators hit a police officer in Mexico City during protests commemorating the 1968 Tlatelolco massacre
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Clashes as Mexico remembers massacre

Riot police have clashed with protesters in Mexico City during a demonstration commemorating the 45th anniversary of a student massacre.

Protesters, some of them masked, threw firebombs, bottles and rocks at police who battled to disperse the crowd.

At least 40 people were injured, Mexico's El Universal newspaper reported.

The rally marked the anniversary of the 1968 killings of student protesters in Tlatelolco Square.