The Hague, March 3: A blast smashed five windows at a coronavirus testing center in a small Dutch town early Wednesday and explosive experts were called in to investigate, 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. Netherlands: Blast Hits COVID-19 Testing Centre in Bovenkarspel.

Police spokesman Menno Hartenberg said it was unclear whether the testing center was deliberately targeted or when the facility would be able to reopen. He said it was clear that the explosive didn't "get there by accident. But we have no idea at the moment who exactly left it there and what the intention was.” Police said a metal cylinder that had exploded was found outside the building.

The northern regions of North Holland province have been identified as a virus hotspot in recent weeks, with infection numbers higher than the national average.

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.

Attacks health workers and facilities around the world have increased amid the COVID-19 pandemic. A new report by the Geneva-based Insecurity Insight and the University of California, Berkeley's Human Rights Center identified more than 1,100 threats or acts of violence against health care workers and facilities last year.

Some Dutch lockdown restrictions were relaxed Wednesday with hairdressers, masseurs and other “contact professions” allowed to reopen if they adhere to strict social distancing and hygiene measures.

Nonessential shops also were allowed to reopen in the Netherlands for the first time since mid-December, though only to very limited numbers of customers who make an appointment in advance.