Actor Yoo Ah-in has tested positive for marijuana after undergoing a drug test as part of a probe into his alleged illegal use of an anesthetic medication, police officials said Friday.

Police sent his hair and urine samples to the National Forensic Service for testing Sunday when he arrived here from the United States over his alleged use of propofol for non-medical purposes.

His urine sample came back positive for cannabis, classified as an illegal drug here, while results from his hair sample have not yet been released, according to the officials.

Police officials view that Yoo has taken propofol in numerous hospitals since 2021 based on an investigation request by the Ministry of Food and Drug Safety. The Seoul Metropolitan Police Agency's drug investigation unit questioned Yoo on Monday.

They raided multiple clinics and hospitals, including those that specialize in plastic surgery, in the southern ward of Gangnam and the central ward of Yongsan on Wednesday and Thursday to seize medical records for evidence.

Yoo's agency vowed to cooperate with the ongoing investigation.

"(We) have yet to be notified by the police of the drug test results," an official at United Arts Agency, said. "As we have said in our statement, (Yoo) will actively cooperate with all related investigations."