WASHINGTON (AP) — The Federal Aviation Administration says an "automation problem" that snarled air traffic throughout a large swatch of the Northeast stretching from New York down to the Carolinas has been resolved.

The agency said that a computer system at an air traffic center in Leesburg, Va., that controllers use to direct high-altitude flights was back in service, and that officials were expected to have lifted any remaining order to hold planes on the ground by about 4 p.m. EDT.

The FAA said it is continuing to investigate the root cause of the problem, and was working closely with the airlines to minimize impacts to travelers.

Information posted online by the FAA indicated that the problem concerned the En Route Automation Modernization computer system, also known as ERAM.

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