12:06 A.M. DEC. 18 UPDATE: Power has been restored on all concourses. More than 5,000 meals are being delivered to passengers. Trains will be operational soon. 11:20 P.M. UPDATE: Power has been restored to the airport’s Atrium and Concourses T, A and B. 10:30 P.M. UPDATE: Atlanta Mayor Kasim Reed says all passengers have been allowed to get off planes that have been stranded for hours. 9:45 P.M. UPDATE: Delta Air Lines cancels 300 flights on Monday. 9 P.M. UPDATE: Mayor Kasim Reed started off an evening news conference with an apology. “First and most importantly, I was to express my sincere apologies to the thousands of passengers whose day has been disrupted in this manner,” he said. “We certainly understand that the outage has caused frustration and anger, and we’re doing everything that we can to get folks back home right away.” Reed said the outage started shortly after 1 p.m., at one of the three Georgia Power substations at the airport. It was caused by an electrical fire that started some time between 12:30 and 12:45 p.m. 8:30 P.M. UPDATE: The Federal Aviation Administration will retain normal staffing in the Air Traffic Control Tower at Hartsfield-Jackson Atlanta International Airport as the airport is open and accepting general aviation and cargo operations. Air traffic controllers also will be ready to handle commercial flights as soon as they resume. 8:25 P.M. UPDATE: Mayor Kasim Reed will hold a press conference at 8:30 at the Airport Emergency Operations Center along with Georgia Power CEO Paul Bowers, Police Chief Erika Shields and airport General Manager Roosevelt Council about the power outage at Hartsfield-Jackson Atlanta International Airport and the multi-agency, coordinated response effort. 7:40 P.M. UPDATE: Mayor Kasim Reed has tweeted: Power at Concourse F is back on. If you are in another concourse, please remain there. We have an additional update on when full power will be restored from. ORIGINAL STORY: Nearly six hours after a power outage began at Hartsfield-Jackson international Airport, officials said a fire likely caused the outage. But the cause of the outage is still not confirmed, officials with Georgia Power said. Atlanta police sent extra officers to help. >> Read more trending news “We are aware of the situation and are assisting with crowd control and helping to manage traffic around the airport,” police spokeswoman officer Lisa Bender said. All flights were canceled,and baggage is being held in a secure area for future pickup, said Rick Crotts, an Atlanta Journal-Constitution editor who was stuck on a plane for hours. Camp Creek Parkway was also shut down, and Atlanta police discouraged anyone from heading toward the airport. Inside the airport, a swirling mass of people waited in an aimless pattern, trying to get cellphone signals in a darkening airport as passengers sat stranded in parked planes on the tarmac. The terminals were pitch black and people had to use cellphones to light their path. People in wheelchairs had to be carried down stopped escalators and stairwells. Delta Air Lines released a statement, saying, in part, that the outage was ongoing and they were “working to deplane customers from aircraft that have not been able to park at a gate due to the outage.” Olivia Dorfman described by phone to The AJC what she witnessed in Concourse D when the power went out. “Maybe 10 minutes later a buzzer went off in the background -- that has been going on for over an hour and every so often bright lights flash in the ceiling,” Dorfman said. Near the D9A gate, she said smoke filled the area, and at different times airport workers tried to herd passengers toward the smoky area and away from it. “This has been very bizarre,” she said. “No one seems to know what they’re doing.” After at least one other woman said she wouldn’t stand in the area that smelled of acrid smoke, as if from an electrical fire, because she suffers from asthma. She and others then walked back toward the gate, Dorfman said. “A man is just yelling, ‘Go this way,’” Dorfman said. She said the stores weren’t able to sell water or other items because of the power outage. “It’s unbelievable. This is the busiest airport,” Dorfman said. Malou Cadavillo and her 16-month-old granddaughter sat in the dark at Hartsfield-Jackson on a motionless luggage carousel, waiting. Her grandchild’s car seat looked like it would never arrive. She described her family’s journey from the gate where they arrived in the afternoon to the terminal as a scary odyssey. They walked through the dark corridor between concourses, guided by the lights of other people’s cellphones, as smoke poured in from some unknown source. Her grandsons, 7 and 11, were uneasy. “I hope there’s no monsters down here,” one said. Her son-in-law Michael Rances said emergency preparedness at the airport was unsatisfactory. “There was nobody there to tell you what to do,” he said. Nearby, a group of Delta pilots stood conferring. “This is gonna take hours,” said one. “Days,” said another. Crotts, who was aboard Flight 3392 that arrived at the airport at 1:31 p.m., was among passengers waiting aboard their flights to reach a gate. Crotts' flight had been waiting for more than two hours when crews brought a ladder and started getting people off the plane, he said. Andy Gobeil, a spokesman for the airport, said officials weren’t sure what happened. “We have not determined what caused it,” Gobeil said. Atlanta fire officials and others are “trying to determine how long it will take to get everything up and running.” Passenger Norman Radow emailed The Atlanta Journal-Constitution after he heard an announcement at the airport that all flights through Atlanta from Johnson City were canceled. “To quote the announcer, ‘I recommend you rebook on Tuesday as it will take days for us to get out of this mess,’” Radow said. He was hopeful his flight wouldn’t be canceled. John Reetz, a passenger on Flight 5297, said his was one of more than 40 planes parked on the tarmac, waiting for power to be restored. At first, the pilot told passengers there was no estimate on when the power would be restored, Reetz said in an email. At the time, passegners were in a generally good mood, but at least one joked that he didn’t have to use the restroom until he saw a line. That was after only 45 minutes, Reetz said. Later, an officer onboard the flight told passengers, '’This looks like it's going to be a longer process now instead of a shorter one,’” Reetz said. “We're going to be here for a while unfortunately.' Ina Bond, 72, was at her wit’s end after having been stranded on the tarmac for three hours. “With water and pretzels and a nasty bathroom,” she said. Looking for a taxi to find a hotel to spend the night after her connecting flight to Delray Beach, Florida, was canceled, Bond could get no information from airport officials. “I passed a whole line of policemen, and none of them could tell me anything,” she said.