Forty-two policemen have been decapitated after being ambushed by a militia group in Congo, officials report.

A demonstration against Mexico's 20% petrol price rise turned violent after a lone protester drove his truck into a line of police guarding a fuel distribution terminal in Baja California.

A police officer has died and another has been hurt after they were shot in San Diego.

Latest: US President Barack Obama said he condemns, in the strongest sense of the word, the attack on police officers in Baton Rouge.