United Airlines has confirmed its plans to fire employees who defied its vaccine mandate.
The Chicago-based airline said it would start the process of firing 593 employees who failed to comply with its COVID-19 vaccination policy.
In early August, United became the first U.S. carrier to require vaccinations for all domestic employees, requiring proof of vaccination by Monday.
The company had plans to put employees who received religious exemptions on temporary, unpaid personal leave starting next week. Those plans, however, have been put on hold because of a lawsuit challenging the policy.
Six United employees filed a class action at the federal court in Texas last week claiming that workers who sought exemptions from the vaccine mandate were subjected to intrusive inquiries about their medical conditions or religious beliefs, including a requirement that they obtain letters from pastors.
United said it has received requests for vaccine exemptions for religious or medical reasons from less than 3 percent of the airline's U.S. workforce of 67,000.
Excluding those who have sought an exemption, United said more than 99 percent of U.S.-based employees have been vaccinated against COVID-19.
United Airlines Chief Executive Scott Kirby said a vaccinated workforce will allow the airline to address any operational requirement.
"We have planned and prepared for this that we are now able to confidently run a strong operation," he said.
Kirby said the airline would follow the guidelines from the U.S. Centers for Disease Control and Prevention (CDC) in making a decision on whether to mandate COVID-19 vaccine booster shots.