JBS SA, the world’s biggest meat supplier, has been targeted in a cybersecurity attack that shut down its North American and Australian computer networks in the latest threat to pandemic-rattled global food supply chains.

JBS USA said it was the target of an organized cybersecurity attack on Sunday, affecting some servers supporting its North American and Australian IT systems, according to an email sent by the company Monday afternoon. The company said it suspended all affected systems and the incident may delay certain transactions with customers and suppliers.

The attack has sidelined two shifts and halted processing at one of Canada’s largest meatpacking plants, while the Australian Financial Review earlier reported that cattle and sheep slaughter had been suspended at its JBS meatworks operations in Australia, citing JBS Australia’s chief executive Brent Eastwood.

A cyber attack presents another headwind for JBS, whose operations recently recovered from workers’ absenteeism due to COVID-19 outbreaks. The meatpacking industry has been trying to push past a dark period during the pandemic, with companies struggling to contain outbreaks that forced many plants to temporarily close or reduce output.

The incident comes about three weeks after a ransomware attack forced Colonial Pipeline Co., operator of the biggest gasoline pipeline in the U.S., to stop the flow of fuel for several days, causing severe gasoline shortages in some areas.

JBS’s incident has affected a Canadian beef plant in Brooks, Alberta, about 120 miles east of Calgary, according to Scott Payne, spokesman for United Food and Commercial Workers Local 401.

“There are no unionized workers there,” Payne said in a phone interview. “That means effectively the plant’s operations have shut for the day.”

Sao Paulo-based JBS owns facilities in 20 countries. Australia and New Zealand account for 4% of the company’s revenue, compared with 50% for the U.S. and 3% for Canada, according to company fillings. The company did not immediately respond to requests for comment on the Canadian closure.