Two police offers were shot in a pizza restaurant in Las Vegas during a shooting spree that left at least three dead.
According to the Associated Press news agency, police said two suspects shot two officers who were eating lunch, with one shouting: "This is a revolution."
They were then said to have fled to Walmart across the street, where they shot a person before killing themselves.
The condition of the officers is not immediately known, the police spokesman said.
More top news
An owner says his video shows one of his pet dogs crying and mourning the death of other pet.
New study says migrant voters could have a "decisive" impact in a range of key marginal seats in the forthcoming general election.
Andy Murray will play world number one Novak Djokovic in Sunday's Australian Open final after the Serbian beat Stan Wawrinka in five sets