A Spanish passenger plane crashed on takeoff from Madrid's Barajas International Airport Wednesday.
According to the airport authority and local media reports, the Spanair plane shot off the runway near Terminal 4.
Officials told The Associated Press that 153 people onboard the aircraft had been killed.
A Spanish emergency rescue official told the AP that 26 people survived the crash, and the rest of those onboard had been given up for dead. The official with the SAMUR municipal rescue service gave the toll after touring the site of the crash.
Earlier today, Spain's El Mundo newspaper reported that 150 people had been killed in the crash, and another 20 were believed to be critically injured.
Spanair spokesman Sergio Allard told a news conference the plane was carrying 175 people and the cause of the crash was not immediately known.
Spanish newspaper El Pais said the the plane had been an hour late taking off due to technical problems. The plane eventually managed to get slightly off the ground but crashed near the end of the runway, El Pais said, quoting an employee of the national airport authority AENA.
Helicopters and fire trucks dumped water on the plane, which ended up in a wooded area at the end of the runway.
A makeshift morgue was set up at the city's main convention center, officials said.
According to El Mundo, so far, between 20 and 30 people have been evacuated from the plane, some of them in critical condition. One of the people wounded is now believed to have died on the way to the hospital.
At La Paz hospital in Madrid, many of the wounded are said to be suffering third-degree burns. A hospital spokesman told ABC News that six people had been admitted to the hospital.
Ambulances are continuing to arrive at that hospital, and at the Ramon y Cajal hospital next door, carrying passengers who are seriously wounded.
The Spanish Prime Minister Jose Luis Rodriguez Zapatero and the Madrid Mayor Alberto Ruiz-Gallardón Jiménez are both making their way to the scene.
According to eyewitness reports from the El Pais Web site, "The plane was all broken and bodies were everywhere."
"I have not seen something like that in my life," said Luis Ferreras, chief of one of the ambulance posts sent to the accident site. There are now 60 ambulances on this location, according to El Pais.
Scotsman Allan Gemmell witnessed the crash, as he was on a neighboring plane.
"Most people, because they just saw the smoke, they didn't do much -- they thought a field was on fire," Gemmell told ABC News.
"When people realized something had happened, they started to phone people," he recalled, adding, "You could see a lot of worry on people's faces."
According to initial reports, the Spanair plane skid off the runway before crashing into the buses parked on the perimeter road.
El Mundo reported that one of the plane's engines may have caught fire on takeoff. Nearly two hours after it caught fire, firefighters were still attempting to extinguish the fire. Eleven fire engines have been dispatched to the scene of the accident.
El Mundo reported that the plane, which may still have people inside it, had split into two parts.
Flight JKK 5022 was bound for Las Palmas in the Grand Canary Islands. The BBC reported that a lot of the people onboard the aircraft were families with young children.
El Mundo reported that officials expect a high number of German casualties, since this flight was operating in conjunction with Lufthansa.
The Swedish ministry spokeswoman Gufran Al-Nadaf told Agence France-Presse that two Swedes were among the people onboard the plane.
"One person has been located in the hospital," Al-Nadaf told AFP. The whereabouts of the second are still not known, she said.
Spanish TV channel Telemadrid reported that the accident happened at 2.45 p.m. local time. Diana Paz, a reporter for Telemadrid, said that 27 people are known to have survived the accident.
That number was also reported by El Pais, which said that eight of those who have survived are in critical condition.
BBC reports that the scene of the accident has now "quieted down" with "at least 70 ambulances" having left the site, carrying wounded to nearby hospitals.
Eyewitness Gemmell told ABC News that "The roads into the airport had been cut off initially, because there were so many ambulances arriving." He estimated that there must have been "at least 80, 90 ambulances" there.
Olivia Acousta, spokeswoman for the Spanish Red Cross in Madrid told the BBC that the Red Cross was giving support to families in Madrid and in the Canary Islands.
She added that the Red Cross is also providing ambulances to take survivors to nearby hospitals.
"Most of people we're sending to hospital have burn problems in their bodies, some of them in very bad condition and some of them in not very bad condition," Acousta said.
Spanair is a subsidiary of Scandinavian Airlines Systems, which issued a statement saying that "Spanair is doing everything possible to assist the Spanish authorities at this difficult time. Spanair will provide further information as soon as it becomes available."
An SAS spokesperson, Henrietta Ellekrog, spoke to the BBC, saying that she could confirm if "a significant number of people have died" in the accident.
Ellekrog said the airline had no details yet about the reasons behind the accident but that finding a reason was "second priority at this moment."
She said that the airline's chief executive was on his way to Madrid. El Mundo reported that Spanair's board of directors had convened an emergency meeting.
Aviation expert Chris Yates defended the airline in an interview with the BBC, saying that Spanair "has a very good safety record."
Family members of the passengers onboard the plane have begun to arrive at the airport, where they are being accommodated in a special crisis room as rescue efforts continue. Spanair has now set up a helpline for families and friends of the passengers (+34 800 400 200).
The runway has now been closed, but other flights are continuing to take off from Madrid airport.
ABC News' Zoe Magee and Eliza Browning in London, Eduardo Sunol in New York, The Associated Press, Agence France-Presse and Reuters contributed to this story.