THE HAGUE, Netherlands (AP) — A police officer in the northern Dutch city of Groningen was stabbed in the face when he attempted to check why two young men were outside during the national coronavirus curfew, the city's police force said.

The officer was taken to a hospital with a serious facial injury, police said in a tweet.

The two young men fled on foot after the stabbing Wednesday night. Police launched a hunt for them and appealed for witnesses.

The 9 p.m.-to-4:30 a.m. Dutch curfew sparked rioting when it was introduced late in January but has been largely adhered to throughout the country since then. Prime Minister Mark Rutte this week extended the measure until the end of the month, when it will be reviewed again.

Coronavirus infections remained stable over the last week in the Netherlands, where more than 16,000 people are confirmed to have died of COVID-19.