Hundreds of flights have been grounded and multiple airports are closed following a global technology outage. The Federal Aviation Administration said Friday it is closely monitoring the issue, which is impacting IT systems at several U.S. airlines that have requested ground stops.

Airports in Boston, Las Vegas; Milwaukee; New York (LaGuardia); Sonoma County, California; and the Virgin Islands are closed. Airports in Atlanta; Charlotte, North Carolina; Detroit; Newark, New Jersey; and Minneapolis-St. Paul have all issued ground delays.

"We’re continuing to address effects on transportation systems from today’s widespread tech outage," Transportation Secretary Pete Buttigieg said in a post on X, formerly Twitter. "Many flights are impacted as systems recover—passengers should check with their airline for updates and visit our website for more on passenger protections.

The technology issue causing the airport disruptions is linked to the cybersecurity company CrowdStrike, which deployed a faulty update to computers that run Microsoft Windows. It was not a cyberattack, the company said. The company said it is working to fix the issue.