State media say an attacker has stabbed four judges with a knife smuggled into a courthouse in central China.

The website of China National Radio said a suspect was arrested after the attack Wednesday morning at the No. 1 Intermediate Court in the Hubei province city of Shiyan. One judge was seriously injured.

CNR says the suspect was arrested in the courthouse basement and had apparently smuggled a knife past security at the courthouse's front door.

CNR quoted Shiyan city government spokesman Qu Wanyong as saying that the suspect was involved in a labor dispute being heard by the court.