BOSTON — Police in Los Angeles, New York City, London, Washington and other cities worldwide stepped up security Monday following explosions at the Boston Marathon.
In Los Angeles, the Sheriff's Department activated its emergency operations center and increased patrols at transit hubs, schools and county buildings, while in New York, critical response teams were deployed citywide and officials stepped up security at hotels and other prominent locations.
California emergency management officials activated their statewide threat assessment system, which was established after the Sept. 11, 2001, World Trade Center attacks. And officials in multiple cities and counties throughout the state were reviewing information from federal authorities for possible threats.
Meanwhile, police in Washington, San Diego, Las Vegas, Detroit and Atlanta were monitoring events closely and assessing potential increases in security measures.
At the White House, the Secret Service quickly expanded its security perimeter, shutting down Pennsylvania Avenue and cordoning off the area with yellow police tape. Several Secret Service patrol cars blocked off entry points to the road, though the White House was not on lockdown and tourists and other onlookers were still allowed in the park across the street.
Agencies were also stepping up their social media response, telling the public via Twitter and Facebook to report suspicious activity to the police.
In Seattle, police increased patrols in neighborhoods and around government buildings and other facilities. In Colorado a statewide alert was sent out advising law enforcement agencies to look out for suspicious activities.
Police at three major Los Angeles area airports, including Los Angeles International, were in a "heightened state of vigilance," with increased patrols, said Chief of Airport Police Patrick Gannon.
"We have no indications that suggest there's a nexus from Boston to the Los Angeles airport, but in an overabundance of caution, we have heightened our patrols," Gannon said.