The FBI is reporting an increase in the number of law enforcement officers from across the country who were killed in the line of duty last year.

Preliminary statistics issued Monday during National Police Week show that 51 officers were killed on duty in 2014, compared to 27 the year before. That was lower than usual.

Almost all of those who died were shot to death, including during ambushes, traffic stops or after answering disturbance calls.

The slain officers include two in New York City who were ambushed last December while sitting in their patrol car.

Besides those slain on duty, the FBI says an additional 44 officers died accidentally while on the job.

The FBI says final statistics and complete details will be published in the fall.

(AP)