UPDATED: Delta flights returning to normal after nationwide ground stop due to IT problem

<p>Delta Airlines customers wait to have their baggage checked at San Francisco International Airport (SFO) January 12, 2010 in San Francisco, California.&nbsp;(Photo by Justin Sullivan/Getty Images)</p>

Credit: 2010 Getty Images

Credit: 2010 Getty Images

<p>Delta Airlines customers wait to have their baggage checked at San Francisco International Airport (SFO) January 12, 2010 in San Francisco, California.&nbsp;(Photo by Justin Sullivan/Getty Images)</p>

Delta Air Lines said its operations were returning to normal Tuesday evening after a nationwide ground stop caused by a technology problem.

Atlanta-based Delta said after 9 p.m. that it had restored all of its information technology systems after a problem affected some of them. The problem had started earlier in the evening.

Delta said it was working to rebook passengers whose flights were disrupted.

“We apologize to all customers for this inconvenience,” the company said in a written statement.

With the systems restored, passengers are able to check their flight status on Delta’s website or app, and check in and book flights.

According to the Federal Aviation Administration air traffic control system command center, Delta had requested that all departing traffic not be allowed to depart until 8:45 p.m. Eastern.

Another FAA status update showed that Delta requested that departing flights destined for Delta hubs at Hartsfield-Jackson International and New York’s JFK and LaGuardia airports not be allowed depart until 9:45 p.m. or later.

The ground stop did not affect flights in the air.

On Twitter, frustrated passengers raised concerns about their flights being delayed.

Hartsfield-Jackson posted on Twitter that at the Atlanta airport, only Delta was affected.

The problem also affected customers trying to book flights on Delta’s website.