Hundreds of United Airlines flights were grounded for hours on Wednesday after computer problems hit the airlines for the second time in the last two months.

A White House spokesman informed that President Barack Obama was briefed on the glitch and it is unlikely that it was unrelated to an outage hours later at the New York Stock Exchange.

"There is no indication at this point either that there is malicious activity involved," said the spokesman, Josh Earnest.

A United spokeswoman said an internal technology issue caused the glitch and it was not due to any outside threat or hacker.

Spokeswoman Jennifer Dohm said that a router problem reduced "network connectivity" for several software applications. "We fixed the router issue, which is enabling us to restore normal functions," she said around midday.

The ground-stop order was lifted by Federal Aviation Administration after nearly two hours, after which the United planes started to fly again Wednesday morning. But delays remained in place as the airline struggled to bring the schedule under its control.

United is the second-biggest airline in the US and Wednesday's outage delayed more than 1,150 flights and led to the cancellation of about 60 flights by late afternoon.

It may be recalled that on June 2, the airline briefly halted all takeoffs in the US due to some problem in its flight-dispatching system. At that time, about 150 flights were affected.

United also faced a series of computer outages in 2012 after switching to the passenger-information system of Continental Airlines after that carrier merged with United. Those outages also delayed hundreds of flights.