An EgyptAir flight en route from Paris to Cairo fell out of the sky over the Mediterranean Sea early Thursday with 66 people onboard, and Egyptian officials said terrorism was the more likely culprit than technical problems.
EgyptAir retracted its announcement that debris from Flight MS804 was found during search operations in the Mediterranean near the Greek island of Karpathos. "We stand corrected on that," the airline told CNN, saying initial information from "official channels" was incorrect.
The jetliner was carrying 66 people when it left Charles de Gaulle Airport at 11:09 p.m. Wednesday Paris time (5:09 p.m. ET), and it vanished shortly before it was due to arrive in Egypt. The Greek defense minister said radar indicated that the plane made two sharp turns and dropped more than 25,000 feet.
French President Francois Hollande said earlier at a news conference that the plane had crashed, but he said it was too soon to speculate as to the cause.
"No hypothesis can be ruled out," he said.
Egyptian Civil Aviation Minister Sherif Fathy also stressed that he would not speculate about what happened, but when pressed by reporters, he said the possibility of a terrorist attack was stronger than that of a technical failure.
He shied away from using the term "crash," however, saying he would use the term "missing" until wreckage was found in order to be "practical."
A senior U.S. intelligence official familiar with the United States' capabilities in the region told NBC News that infrared and multi-spectral imagers suggest that an explosion occurred on the flight. He reaffirmed that a cause of the crash remains unknown, and Egyptian officials have not commented on any possible blast.
Egyptian and Greek authorities are searching for the plane, which was flying at nearly 37,000 feet when it disappeared from radar with about a half-hour left of a 3½-hour flight.
Almost immediately after entering Egyptian airspace, the plane swerved sharply and then lost altitude before it dropped off radar, Greek Defense Minister Panos Kammenos said at a news conference.
At 37,000 feet, the plane "executed a turn of 90 degrees left and then a turn of 360 degrees toward the right, dropping from 37,000 to 15,000 feet, and then the picture we had was lost at about 10,000 feet."
When the plane vanished, it was about 175 miles from Egypt's coast, according to officials. Radar showed no adverse weather in the area at the time the jet disappeared.
There were 56 passengers — including three children — along with seven crew members and three "security" personnel on board the Airbus A320, EgyptAir said. The airline initially had said 69 people were on board, but it later revised the figure.
The passengers included 30 Egyptian nationals, along with citizens from 11 other countries, among them Canada, France, Britain , Belgium and Iraq.
Britain's Foreign Office told NBC News that it was "in urgent contact with local authorities in Paris and Cairo," and the French Foreign Affairs Ministry opened a crisis hotline.
Egyptian and Greek authorities were focusing search efforts in the Mediterranean Sea, with assists from other nations. The Greek military confirmed that one of its frigates and two of its aircraft were involved in a search about 130 nautical miles south-southeast of the island of Karpathos.
The U.S. Navy also said that — at the request of the Greek government — one of its P-3 aircraft had joined the search.
Greek air traffic controllers had a normal interaction with the pilot as he flew above the island of Kea, according to the head of the country's civil aviation authority.
Kostas Lyntzerikos told NBC News that he plane exited Greek airspace at 3:26 a.m. local time (8:26 p.m. ET Wednesday) and disappeared from radar screens two minutes later — at which point controllers notified Egyptian authorities.
The Paris prosecutor's office confirmed that it had opened an investigation. France's aviation authority, the BEA, said it was in contact with Egyptian authorities and was taking part in the investigation.
The British Air Accidents Investigation Branch, meanwhile, said it had offered to assist Egypt's authorities, as well.
Airbus — the maker of the plane — said the plane was made in 2003 and delivered to EgyptAir in 2008, adding that the aircraft had accumulated about 48,000 flight hours. EgyptAir said the pilot had 6,275 flying hours, while the co-pilot had 2,766.
Authorities stressed the need to protect relatives of the passengers, and the names of the passengers and the crew have not been publicly released.
French Foreign Minister Jean-Marc Ayrault met with families who gathered at the Paris airport and told reporters theat it was clearly an emotional time.
He, too, urged a halt to speculation out of respect for the families, saying that supporting them was the first "priority."
Anguished relatives also gathered at the Cairo airport. The Associated Press reported that doctors were brought in after distressed family members collapsed.
While there was no immediate indication of whether terrorism was involved, Egyptian aviation security has been under scrutiny since a passenger jet crashed after taking off from Sharm el-Sheikh airport in October.
ISIS claimed responsibility for downing the Metrojet plane, and the incident raised questions about how any potential explosives could have been smuggled on board and whether there were security failings on Egypt's end.
Analysts were cautious, but they said terrorism could not be ruled out.
"The current indications are leaning toward some sort of abrupt incident, as opposed to some sort of gradual malfunction," said Daniel Nisman, a security analyst at the Levantine Group.
Nisman pointed to the altitude of the plane — which he said suggested that there had not been an attempt to descend because of, say, a loss of cabin pressure or engine failure.
"It doesn't exhibit the normal features of something accidental," he said. "Nothing should be ruled out — but that also means that malicious intent shouldn't be ruled out, either."
"If — and totally if — it was malicious intent then it could be that it was done in order to send some sort of a message," Nisman added, noting that Egypt has been a focus of ISIS propaganda.
Pointing to the Metrojet crash, Nisman said "you also have precedent, unfortunately," for Egypt's being a target.
Still, Nisman added, if a security lapse was to blame, it's "not necessarily" Egypt's fault. "It could mean a security lapse in Europe — which is not good," he said.
This story originally appeared on NBCNews.com.