Boston officials have announced improved public safety measures for the final two miles of the Boston Marathon on April 21, a year after two explosions near the finish line killed three people and wounded more than 260 others.
Mayor Martin Walsh and Police Commissioner William Evans on Saturday said more uniform and undercover officers will be deployed along the marathon's Boston route.
Authorities also have installed more than 100 cameras along the Boston portion, together with 50 observation points that will help monitor the crowd.
Thirteen ambulances will be deployed, together with 140 emergency medical service workers on foot patrol, bicycles, utility vehicles and in medical tents.
Officials urge spectators to leave backpacks, strollers and other large items at home.