PHILADELPHIA (Reuters) - Police in three states were searching on Saturday for a gunman who shot and killed a state trooper in a police barracks in Pennsylvania, a police official said.

The shooting, in which a second soldier was wounded, occurred at the Blooming Grove barracks around 11pm on Friday, said Pennsylvania police spokeswoman Connie Devens.

The shooter remained on the loose on on Saturday morning, Ms Devens said, prompting a manhunt by the police from Pennsylvania, New York and New Jersey.

Footage on local television station WNEP showed police cruisers and SWAT vehicles rushing to the scene while a helicopter hovered overhead.

Blooming Grove is a township of roughly 5,000 people near the New York state border.