Thousands of passengers reported being stranded at airports across the United States, in a delay that was caused because the passport system across the country was down Monday.

Several international travelers, possibly returning from the long New Year weekend, took to Twitter to share pictures and videos of long lines at airport checks and passport kiosks in airports including the John F. Kennedy International Airport in New York, Miami International Airport in Florida and Hartsfield-Jackson Atlanta International Airport in Georgia.

According to the stranded passengers, the delay was because the computer system to check passports, operated by the U.S. Customs and Border Protection, had failed. CBP later put out a statement on its Twitter page, saying all the airports were back online after a brief outage of its processing systems.

"During the disruption, CBP had access to national security-related databases and all travelers were screened according to security standards," it added and also said that disruption did not appear to be of a malicious nature.

Some travelers said they were asked to use mobile passport at the checks.

Meanwhile, the Denver International Airport on its Twitter page confirmed that CBP was facing a computer issue Monday night and warned travelers arriving from international destinations that they may experience delays.

A few minutes later, another tweet said the customs processing issue was resolved.

Several other airports also confirmed the outage.

Strangely, a quite similar incident took place on Jan.2, 2017, almost one year to the date, where extensive delays were caused due to computer outage affecting customs procedures.

At the time, the U.S. Customs and Border Protection agents were forced to process travelers through a slower backup system when the computers went down, NY Daily News said.

A spokeswoman for U.S. Customs did not to comment on what might have caused the glitch then.

“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 spokeswoman said.CBP officers continue to process international travelers using alternative procedures until systems are back online. 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.”