United Airlines Boeing 737
A United Airlines Boeing 737-800 arrives at San Diego International Airport, Feb. 13, 2015. Reuters/Louis Nastro

Update 10.00AM: United Airlines flights across America are apparently back up and running after being grounded since early Wednesday morning.

United Airlines flights across the U.S. have been grounded due to an apparent problem with the carrier's computer reservation system.

"We experienced a network connectivity issue this morning," United confirmed in a statement after 9 a.m. "We are working to resolve this and apologize to our customers for any inconvenience."

All United flights at John F. Kennedy International Airport were canceled Wednesday morning, according to International Business Times reporter Chris Harress, who is at the scene. Multiple passengers are taking to Twitter to provide updates on the situation:

IBTimes searched a number of flights' status and information on the United website, each one returned an error saying: "We could not process your request. Please see the message below and make revisions. We could not find flight details matching your request. Please verify the information and try again or contact Reservations and Information at 1-800-UNITED-1 (1-800-864-8331) elsewhere please use the local phone number for assistance."