Delta: Thousands of passengers stranded by power cut

 Delta passengers in Las Vegas were severely affected by the outage

Thousands of air passengers around the world have been left stranded after a power cut forced the US airline Delta to suspend flights.

The incident caused delays across the US and in Japan, Italy and the UK.

Airport check-in systems, passenger advisory screens, the airline's website and smartphone apps were affected by the systems failure on Monday.

After six hours, Delta said flights had resumed on a limited basis but warned of continuing delays and cancellations.

The airline suspended dozens of departures early on Monday, with airport agents forced to write out boarding passes by hand.

 Delta serves about 180 million customers a year, employing over 80,000 people 

 Some flights from Atlanta have now resumed

"Our systems are down everywhere," the company at one point told its customers on Twitter.

Passengers around the world complained of long check-in queues, with many sleeping on the floor.

A Delta statement said the power cut caused its computer systems to crash.

After the problem was resolved, the airline warned that many passengers still faced delays and cancellations because of the knock-on effect of the earlier disruption.

Delta ranks third in the world in terms of passengers carried, according to industry body the IATA.

The airline has advised customers to check the status of their flight before heading to the airport.

The overnight power failure took place in Atlanta, near Delta's headquarters, the company said.

It will damage Delta's reputation for punctuality and lack of cancellations, USA Today commented.

 Passengers around the world complained of long queues at check-in desks

One passenger told the BBC he was waiting with "several hundred" fellow stranded passengers at San Francisco airport, after being asked to leave a plane he had boarded.

"We were ordered off the plane after approximately an hour or more," said Dick Ginkowski, who said that tempers were starting to get strained.

Delta has been responding to unhappy customers on Twitter.

 A typical exchange between Delta and a social media user

The airline serves about 180 million customers a year, employing over 80,000 people, its website says.

It is the latest carrier to suffer computer problems, with Southwest Airlines last month forced to cancel more than 2,000 flights after an outage prevented travellers checking in.