WALLA WALLA -- A unit at the Washington State Penitentiary remained on lockdown today after an assault on a correctional officer.

Unit G in the prison's West Complex was locked down after the officer was assaulted about 7 p.m. Monday, said Shari Hall, prison spokeswoman. Unit staff responded immediately and the officer was transported to a local hospital and released. The officer sustained no substantial injuries, Hall said in a release.

The unit is one of four close-custody facilities in the West Complex. A total of 187 inmates are affected by the lockdown, which is expected to continue until Friday.

No other areas of the penitentiary have been affected by the lockdown and are on normal status.