Runners in costume train for the Boston Marathon in Newton, Mass., Saturday, March 1, 2014. People running this year's Boston Marathon for charity gathered for a 17-mile training run along the last 17 miles of the course. (AP Photo/Michael Dwyer)
In this April 15, 2013 file photo, a man dressed as a hot dog runs through Wellesley, Mass., during the 117th running of the Boston Marathon. Security will be tightened for the 2014 Boston Marathon after twin explosions killed three people and injured more than 260 near the finish line of the race in 2013. New rules include a limit on the size of water bottles, restrictions on bulky costumes, and nothing covering the face.(AP Photo/Michael Dwyer, File)
FRAMINGHAM, Mass. (AP) — Spectators attending this year's Boston Marathon with backpacks, coolers and other large items will have them subject to search.
Officials on Monday strongly discouraged attendees from bringing such bags and instead urged them to carry belongings in clear plastic bags like those being given to runners to stow their gear.
At least 3,500 police officers will be spread across the eight cities and towns that make up the marathon route. That's more than double the number from last year.
Authorities have been meeting for months to come up with a plan to beef up security following last year's deadly attack. Three people were killed and more than 260 injured after two bombs exploded near the finish line of the race.
This year's race is scheduled for April 21.
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