Three Asian police officers are taking the Northumbria force to an employment tribunal over claims that they were racially abused and received hate mail.

Two sergeants and a constable are taking action against the force.

Northumbria Police said it would not comment on forthcoming cases but defended its race relations.

In a statement the force said: "We take matters of discrimination seriously, and thoroughly investigate any complaints brought to our attention."

It also said it was meeting its current target for "ethnic background" recruitment, and is on course to meet its long term target for 2009.

Ravi Chand, president of the National Black Police Association, said he was very concerned at the nature of the allegations made by the officers.