The number of officers killed in the line of duty was eight more than the 48 slain in 2009, a rise of 16 percent, the FBI said.
In addition to the officers killed in 2010, 72 officers were killed in accidents — an increase of 24 officers when compared with 2009.
All but one of the officers was slain using a firearm. A majority of the slain officers — 38 out of 56 — was wearing body armor.
The only officer who was not a victim of a firearm was killed with a vehicle.
Fifteen of the officers died in ambushes; eight while investigating suspicious persons or activities; seven during traffic stops or pursuits; six after interrupting robberies or pursuing robbery suspects, and six while responding to disturbance calls.
Three of the officers were killed after they interrupted burglaries in progress or while pursuing burglary suspects; three died during tactical situations — such as when an offender is barricaded inside a building –; two while conducting investigations and one while transporting a prisoner.
Of the remaining slain officers, one was killed during a drug-related conflict and four while attempting to make arrests.
The FBI will release final statistics on officers killed and assaulted in the line of duty later this year.