THE HAGUE, Netherlands (AP) — A blast smashed windows at a coronavirus testing center in a small town north of Amsterdam early Wednesday, police said. Nobody was hurt.

Police in the province of North Holland tweeted that “an explosive went off” near the testing center in Bovenkarspel just before 7 a.m.

Police cordoned off the area, which is 60 kilometers (40 miles) north of Amsterdam, and were investigating the cause of the blast.

In January, rioters torched a coronavirus test facility in the fishing village of Urk on the first night of a 9 p.m.-to-4:30 a.m. nationwide curfew imposed as part of the government’s latest coronavirus lockdown.