U.S. technology CEOs including Facebook’s Mark Zuckerberg and Apple’s Tim Cook have pledged to donate masks to medical professionals as large corporations try to do their part to help battle the coronavirus outbreak.

Cook said on Sunday that Apple will donate “millions of masks” for health professionals in the U.S. and Europe.

On the same day, Zuckerberg said Facebook is donating its emergency reserve of 720,000 masks to health workers. Facebook had initially bought them in case the wildfires in California continued. Zuckerberg said the company is also “working on sourcing millions of more to donate.” 

Salesforce CEO Marc Benioff also said Sunday that the company had delivered 9,000 masks to the University of California, San Francisco. 

“We are working hard across all of our resources & relationships to deliver an additional 5 million masks this week plus additional critical PPE (personal protective equipment),” he added.

Tesla CEO Elon Musk said his company is making ventilators and expects to have over 1,200 to distribute this week.

China, which was the epicenter of the coronavirus for a while, has seen a dramatic slowdown of new cases. In fact, China’s National Health Commission said there were 39 new cases as of the end of March 22, all of them imported.

Meanwhile, the virus is spreading to the rest of the world and governments are fighting to get a grip on the situation. The U.S. has quickly become one of the hardest hit nations, with at least 35,000 cases and 471 deaths, according to data collected by Johns Hopkins University.