A nationwide Customs and Border Protection system outage stranded thousands of travelers at airports on Monday.

Folks trying to enter the U.S. via a handful of cities were met with long lines and excessive delays as customs officers manually processed international passengers.

Issues were reported in Atlanta, Ft. Lauderdale, Los Angeles, Miami and Washington, D.C., as well as Baltimore, Boston, Newark and San Francisco. All airports came back online Monday night, following what CBP called “a temporary outage” of its processing systems.

“U.S. Customs and Border Protection is experiencing a temporary outage with its processing systems at various airports of entry and taking immediate action to address the technology disruption,” the agency said in a statement to ABC News.

“CBP officers continue to process international travelers using alternative procedures until systems are back online,” it continued. “Travelers at some ports of entry are experiencing longer than usual wait times and CBP officers are working to process travelers as quickly as possible while maintaining the highest levels of security.”

U.S. Customs and Border Protection did not immediately respond to PCMag‘s request for comment. According to a tweet, however, there is no indication the disruption was malicious.

According to social media accounts, conditions at Miami International Airport were particularly harsh: an army of angry, hungry people crowded the hallways for three-plus hours as rising temperatures caused fainting and vomiting.

@cnnbrk please let US Customs know the Miami airport could use a little help. Thousands of us waiting in a “line”. pic.twitter.com/VGLUOUiaoP

— Garret Prather (@garretp) January 3, 2017

@wsvn immigration @ M.I.A. Hundreds waiting, system has been down for hours pic.twitter.com/kuyR9u7boO

— Reza (@EGerami) January 3, 2017

Nightmare at the #Miami airport for all incoming int’l flights: all systems were down at immigration. Hours of wait #miamiairport pic.twitter.com/MOorFyfv9x

— Sarah (@iLoveSassou) January 3, 2017

Similar scenes were depicted at Washington Dulles International Airport, where Twitter user Richard Walker documented “36 unusable passport express kiosks, 20 unused global entry” stalls, eight agents and a one-hour wait.