A U.S. labor and activist coalition said employees of Amazon.com Inc. would take off work starting on Tuesday to draw attention to what it says are unsafe conditions at warehouses during the coronavirus pandemic.

The action involves more than 350 of Amazon's staff from 40 facilities, according to the coalition. The world's largest online retailer has faced several worker protests and demands by unions for it to close warehouses down.

The virus has infected more than 2.4 million people globally including Amazon warehouse staff, and it has given voice to labor activists at the retailer. However, organizing has remained limited and has not hampered operations at a company with more than 590,000 employees in the United States.

Reuters was unable to verify the numbers shared by the coalition, known as Athena. Amazon said reports of workers' participation were "grossly exaggerated."

In a video that Athena posted on Twitter, worker Phillip Anthony Ruiz said, "I am not going in today because Amazon is putting our lives at risk."

Facility closures would hinder Amazon's ability to deliver essential goods during the pandemic, with the vast majority of the U.S. population under government stay-at-home orders. The company has focused on preventive health measures to keep work sites open: increasing sanitation, mandating social distancing, giving employees face masks and taking their temperatures.

"More than 250,000 people have come to work today, even more than last week to serve their communities," Amazon said in a statement. "We encourage anyone to compare the health and safety measures Amazon has taken, and the speed of their implementation, during this crisis with other retailers."

Cases of the virus have been reported among staff from more than 50 of Amazon's U.S. warehouses, according to the New York Times. Amazon (AMZN) has 519 facilities in its U.S. distribution infrastructure, according to logistics consultancy MWPVL International Inc.