Authorities in major American cities have stepped up security precautions after Monday's deadly blasts in Boston. Two explosions at the Boston Marathon killed at least three people and injured scores of others.
Los Angeles police posted additional officers at transit hubs and in other public places. They say there is no indication the Boston explosions suggest a threat to Los Angeles, but that they implemented the actions to reassure residents. Police in New York, Washington, Las Vegas, Detroit and Atlanta say they are monitoring events closely.
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Law enforcement agencies have converged on Boston and Suffolk County District Attorney Daniel Conley says help has come from many places.
“Police and medical personnel from across the region have sent dozens, maybe even hundreds, of volunteers to help us here in Boston," said Conley. "That's what Americans do in times of crisis. We come together and we help one another.”
Police in London say the explosions have prompted a security review of this Sunday's London Marathon, the world's largest long-distance running event. It drew 37,000 runners and half a million spectators last year.
In Los Angeles, security was heightened Monday evening at Dodger stadium, where the L.A. Dodgers faced off in a baseball game against the San Diego Padres.
Sports facilities from Miami to Nashville reported extra security for Monday's games, including added patrols and police dogs and many stadiums observed a moment of silence for the Boston victims.