Authorities laid out a broad security plan Monday for the Boston Marathon — cameras along the route, checkpoints for spectators, National Guard troops and more than 3,500 police officers — and told fans to leave their backpacks at home.
They urged the 1 million people expected to watch the race on April 21 to carry personal items in clear plastic bags instead, both to help security officers and to ease the nerves of other fans.
Backpacks have already been banned for the 36,000 runners in the race. The two bombs that exploded last year near the finish line, killing three people and injuring more than 260, were hidden in backpacks.
The authorities also strongly discouraged people from jumping onto the course, as they traditionally do, to run a portion of the race alongside friends and relatives making the full, 26.2-mile run.
But they said they would make no effort to keep people away from Boylston Street, where the bombs went off last year.
“We are encouraging the public, spectators, to enjoy the day,” said Kurt Schwartz, director of the Massachusetts Emergency Management Agency. “Come out and enjoy the day anywhere along the 26.2 miles.”
Authorities said there was no specific threat to this year’s race.
Besides setting up their own surveillance cameras, authorities are working with businesses along the route that may have their own cameras and can turn them to face the course, said Col. Tim Alben of the Massachusetts State Police.
The National Guard will deploy 400 soldiers, trained as military police, along the course, and the 3,500 police officers will spread out among eight cities and towns that take part in the race.