Thousands of police officers will fan out across the 42.2-kilometre Boston Marathon course to provide security for the famous race that was marred by a deadly bombing last year.

Public safety officials from the local, state and federal level held a news conference in Framingham, Mass., on Monday to reveal some of the new security measures.

Among the biggest changes is that spectators can expect to have backpacks, coolers and other large items searched. Runners competing in the race already found out last month that they would no longer be able to check backpacks at the beginning of the race to pick up at the end.

Law enforcement officials said over 3,500 police officers — some in uniform and others in plainclothes — will cover the course. There will also be assets from federal organizations on site.

A twin bombing near the finish line of last year’s race killed three people and injured more than 260. Despite the tragedy, the Boston Athletics Association said there will be about 36,000 runners competing and a million spectators lining the course this year.

The race is scheduled for Monday, April 21, which is Patriots’ Day in Massachusetts.

With files from The Associated Press