(Bloomberg) — Amazon.com Inc. Chief Executive Officer Jeff Bezos warned his company’s 800,000 employees that the coronavirus outbreak will likely “get worse before it gets better,” according to an open letter shared Saturday on his Instagram account.

The letter follows cries from U.S. lawmakers and his own employees that the world’s largest online retailer isn’t doing enough to protect its warehouse workers and delivery drivers who endanger themselves delivering products to Amazon customers looking to avoid stores.

“This isn’t business as usual, and it’s a time of great stress and uncertainty,” Bezos wrote. “It’s also a moment in time when the work we’re doing is its most critical.”

Bezos’ letter, his first public comments about the outbreak, comes when lawmakers and regulators around the country are making decisions about which businesses are essential and should keep operating, and which ones should close down so employees can remain at home and reduce their exposure to the outbreak that has infected more than 300,000 globally and killed at least 13,000.

Amazon has seen a surge in demand from customers ordering baby formula, hand sanitizer and medical supplies. It announced plans to hire 100,000 workers to meet demand and is temporarily boosting pay among its warehouse employees and instructed its contract delivery partners to also raise wages for drivers who don’t work directly for Amazon. Key rival Walmart Inc. is also hiring workers and doling out bonuses to staff helping it meet demand.

More Pay

Both companies face criticism from lawmakers, workers and activists for not doing enough to protect hourly workers on the front lines of the crisis. The pressure ramped up Friday when a group of workers from Walmart, Amazon and other big retailers, called United for Respect, demanded paid leave for those affected by the coronavirus outbreak and better protective measures from their employers.

Amazon on Saturday announced hourly workers in its U.S. delivery network would received double pay for every hour they work in excess of 40 each week, effective March 15 through May 9. That follows temporary raises of $2 per hour that will be in effect through April.

Monica Moody, a 22-year-old Amazon warehouse worker near Charlotte, North Carolina, said she and her fellow employees don’t have adequate protective gear or sufficient time to wash their hands during their shifts. She argued that the warehouse should close temporarily to be sanitized.

More Aggressive Measures

Also on Friday, four Democratic senators, led by Cory Booker of New Jersey, wrote to Bezos asking that the company implement more aggressive safety measures and offer more hazard pay to its employees. The letter cited news reports in the past week in which workers at the front lines of Amazon’s logistics network raised concerns they didn’t have the time or resources to protect themselves as they helped speed packages to customer doorsteps. The Amazon delivery drivers in California told Bloomberg they received one single disinfecting wipe to clean vans before the start of their shifts.

Bezos said the company has increased cleaning in its facilities and implemented instructions for employees to maintain a safe distance from one another, and continues to meet daily to address safety issues. Getting proper equipment remains a challenge, he said. On Wednesday, Amazon reported the first confirmed case among its U.S. warehouse workforce — at a delivery station near New York’s LaGuardia Airport.

“We’ve placed purchase orders for millions of face masks we want to give to our employees and contractors who cannot work from home, but very few of those orders have been filled,” Bezos said.

“Masks remain in short supply globally and are at this point being directed by governments to the highest-need facilities like hospitals and clinics,” he added. “It’s easy to understand why the incredible medical providers serving our communities need to be first in line. When our turn for masks comes, our first priority will be getting them in the hands of our employees and partners working to get essential products to people.”

Amazon is now one of the three most biggest U.S. companies by market value, making Bezos the world’s richest man. Critics say he could do more.

“Talk is cheap,” said Dania Rajendra, director of Athena, a group that advocates for hourly workers and small businesses, and a frequent critic of Amazon.

“Rather than focusing on unavailable equipment, or issuing half measures that don’t come close to tackling the scale of the crisis, Bezos and his corporation should make real moves that protect public and worker health, starting with the very basics, like enough time for workers to wash their hands, health coverage for everyone who needs it, and paid leave, so people who need to stay home can,” she said.