Amazon CEO and founder Jeff Bezos on Saturday published an open letter thanking his employees for their work during the coronavirus crisis, offering his support as many of his workers have spoken out for more assistance from the company.

Hundreds of thousands of the e-commerce giant's warehouse workers, along with delivery drivers, have been working to ship packages to millions of customers who are being told to stay home to avoid spreading the virus.

"We're providing a vital service to people everywhere, especially to those, like the elderly, who are most vulnerable. People are depending on us," Bezos wrote on Amazon's company blog, offering his first lengthy public statement amid the pandemic.

"I'm not alone in being grateful for the work you are doing," he continued. "I've received hundreds of emails from customers and seen posts on social media thanking you all. Your efforts are being noticed at the highest levels of government, and President Trump earlier this week thanked this team profusely."

Bezos' comments come as his employees, their supporters and four US senators are calling on the company to do more to support these workers, who aren't able to work from home during the outbreak. These people have said the company has been putting employees and potentially customers in harm's way by not instituting more stringent health requirements. Many of them have called for more paid leave for workers.

These concerns reached greater urgency this week when Amazon disclosed its first confirmed coronavirus case in a US warehouse, which forced it to temporarily shut down the Queens, New York, facility.

While much of Saturday's letter reiterated information Amazon has already made public, Bezos did mention that his company has put in purchase orders for millions of face masks for employees and contractors, but said few of these orders have come through. As masks remain hard to find around the world, governments are directing supplies to medical workers, he said.

Bezos said Amazon's leadership has already instituted many new protocols, including increased cleaning in fulfillment centers. He also reached out to people who have been laid off to come work for Amazon temporarily, as the company this week announced plans to hire 100,000 more US employees to handle the surge in new orders.

"We are meeting every day, working to identify additional ways to improve on these measures," he said about Amazon's safety protocols, later adding: "I want you to know Amazon will continue to do its part, and we won't stop looking for new opportunities to help."