WARSAW (Reuters) – A rapid growth of coronavirus infections among miners at Poland’s state-run coal producer JSW boosted the increase in daily cases to the highest since May 12, data from the health ministry showed on Saturday.

There were 576 new cases in the country, the ministry data showed, of which 346 were linked to the JSW mine at Zofiowka.

The number of new cases at the mine could be similar on Sunday, a health ministry spokesman was quoted as saying by the PAP news agency.

JSW, the European Union’s biggest coking coal producer, said in a statement that it has reported a total of 2,756 coronavirus cases, mostly at the Pniowek and Zofiowka mines. The country’s southern coal region currently has the highest number of infections.

Saturday’s daily increase brings the total number of people infected in the country to 25,986, with 1,153 deaths.

JSW has reduced coal output at Pniowek, while another state-run mining company, PGG, had to close a few mines temporarily in May due to the growing number of infections.

The coronavirus pandemic has aggravated the financial situation of Polish coal mines, which had been struggling with falling demand, low prices and rising stock piles before the outbreak.

The government has said it will announce a restructuring plan for the industry in the coming weeks.

The jump in the daily number of cases coincides with a presidential election campaign, with many candidates out campaigning on Saturday.

Poland set June 28 as a new date for the vote which did not take place as planned last month due to the pandemic.