IOWA PARK, Texas -- A spokesman for the Texas prison system says officials are "closely monitoring" a hunger strike involving about 40 inmates that started eight days ago.

Texas Department of Criminal Justice spokesman Robert Hurst said by email Tuesday that 37 prisoners in segregation are participating. The number has fallen since Sunday, when he told the Houston Chronicle that 45 inmates were involved.

The inmates refusing meals are housed at the Allred Unit in Iowa Park, about 120 miles northwest of Fort Worth near the Oklahoma border. Hurst said they began refusing meals on Christmas but some have food in their cells that they purchased from the commissary.

He said the department "will take appropriate action as needed", but did not elaborate.

Hurst said the inmates have complained about recreational time, food portions and the temperature.