HAMBURG (Reuters) – Some 400 workers have tested positive for the new coronavirus at an abattoir in northern Germany, prompting the closure of local schools and an urgent investigation, officials said on Wednesday.

Toennes, one of Germany’s biggest meat processors, said it had stopped slaughtering on Wednesday and was shutting the abattoir in stages.

The local government authority of Gutersloh, where the plant is located, said it will close schools and kindergartens from Thursday as a precautionary measure.

Germany, which has been relatively successful in containing the new coronavirus, in May announced it was tightening rules on abattoirs.

It decided to ban the subcontracting of meat-packing work through employment agencies after a series of coronavirus outbreaks among slaughterhouse workers, Labour Minister Hubertus Heil said.

Toennes said in a statement the plant’s reopening would depend on what the authorities decide.

The positive tests followed an extensive testing programme, it said across its 19 sites in Germany. Tests at other plants have found no signs of the virus and production elsewhere is continuing, it said.

Globally, abattoirs have been halted as a result of the coronavirus, with U.S. slaughterhouses and meatpacking plants disrupted after a series of positive tests.