Updated at 2 p.m. May 19: Adds information on survivors and identifies some fatalities.

The only three survivors of Cuba's worst aviation disaster in three decades were clinging to life Saturday, a day after their passenger jet carrying 110 people crashed in a fireball in Havana's rural outskirts.

Carlos Alberto Martinez, director of the Calixto Garcia Hospital in the Cuban capital, said doctors are always hopeful that their patients will recover, but he acknowledged that the three Cuban women were in extremely grave condition.

"We must be conscious that they present severe injuries," Martinez told a small group of journalists. "They are in a critical state."

Among the dead are 20 priests from an evangelical church, confirmed Maite Quesada, a member of the Cuban Council of Churches.

Meanwhile relatives of those who died gathered at a morgue in the capital, weeping and embracing each other, as investigators tried to piece together why the aging Boeing 737 went down and erupted in flames shortly after takeoff early Friday afternoon.

1 / 5Picture taken at the scene after a Cubana de Aviacion aircraft crashed after taking off from Havana's Jose Marti airport on May 18, 2018.(ADALBERTO ROQUE / Getty Images) 2 / 5Picture taken at the scene of the accident after a Cubana de Aviacion aircraft crashed after taking off from Havana's Jose Marti airport on May 18, 2018. A Cuban state airways passenger plane with 104 passengers on board crashed on shortly after taking off from Havana's airport, state media reported. The Boeing 737 operated by Cubana de Aviacion crashed "near the international airport," state agency Prensa Latina reported. Airport sources said the jetliner was heading from the capital to the eastern city of Holguin. (ADALBERTO ROQUE / Getty Images) 3 / 5Emergency services arrive at the scene of the accident after a Cubana de Aviacion aircraft crashed after taking off from Havana's Jose Marti airport on May 18, 2018. A Cuban state airways passenger plane with 113 people on board crashed on shortly after taking off from Havana's airport, state media reported. The Boeing 737 operated by Cubana de Aviacion crashed "near the international airport," state agency Prensa Latina reported. Airport sources said the jetliner was heading from the capital to the eastern city of Holguin. (YAMIL LAGE / Getty Images) 4 / 5Emergency personnel works at the site of the accident after a Cubana de Aviacion aircraft crashed after taking off from Havana's Jose Marti airport on May 18, 2018. A Cuban state airways passenger plane with 113 people on board crashed on shortly after taking off from Havana's airport, state media reported. The Boeing 737 operated by Cubana de Aviacion crashed "near the international airport," state agency Prensa Latina reported. Airport sources said the jetliner was heading from the capital to the eastern city of Holguin. (ADALBERTO ROQUE / Getty Images) 5 / 5Cuban President Miguel Diaz-Canel (C) is pictured at the site of the accident after a Cubana de Aviacion aircraft crashed after taking off from Havana's Jose Marti airport on May 18, 2018. A Cuban state airways passenger plane with 113 people on board crashed on shortly after taking off from Havana's airport, state media reported. The Boeing 737 operated by Cubana de Aviacion crashed "near the international airport," state agency Prensa Latina reported. Airport sources said the jetliner was heading from the capital to the eastern city of Holguin. (ADALBERTO ROQUE / Getty Images)

Skies were overcast and rainy at the airport at the time of Cuba's third major air accident since 2010, and state television said the 39-year-old jet veered sharply to the right after departing on a domestic flight to the eastern city of Holguin.

"The only thing we heard, when we were checking in, an explosion, the lights went out in the airport and we looked out and saw black smoke rising and they told us a plane had crashed," Argentine tourist Brian Horanbuena told The Associated Press at the airport.

Cuban President Miguel Diaz-Canel said a special commission had been formed to find the cause of the crash. The plane had 104 passengers and six crew members.

State airline Cubana, which operated the flight, has had a generally good safety record but is notorious for delays and cancellations and has taken many of its planes out of service because of maintenance problems in recent months, prompting it to hire charter aircraft from other companies.

Mexican officials said the Boeing 737-201 was built in 1979 and rented by Cubana from Aerolineas Damojh, a small charter company that also goes by the name Global Air.

Aviation authorities in Guyana last year stopped the same aircraft from conducting charter flights because of serious safety concerns, including fears about excessive baggage overloading and other issues.

A statement from Mexico's Transportation Department identified the pilot and co-pilot as Capt. Jorge Luis Nunez Santos and first officer Miguel Angel Arreola Ramirez. It said the flight attendants were Maria Daniela Rios, Abigail Hernandez Garcia and Beatriz Limon. Global Air said maintenance worker Marco Antonio Lopez Perez was also aboard.

Outside the company's Mexico City offices on Friday, former Global Air flight attendant Ana Marlen Covarrubias said she had worked for the company for over seven years and knows nearly all the crew members.

"I don't have the words. I'm very sad. We're in mourning," she said in tears. "It was something really, really, really terrible; a tragedy for us."

In addition to the Mexican crew, Cuban Communist Party newspaper Granma reported that the passengers were mostly Cubans plus five foreigners from countries it did not identify. Argentina's Foreign Ministry said two of its citizens had died in the crash.

In November 2010 a Global Air flight originating in Mexico City made an emergency landing in Puerto Vallarta because its front landing gear did not deploy. The fire was quickly extinguished, and none of the 104 people aboard were injured. That plane was a 737 first put into service in 1975.

Mexican aviation authorities said a team of experts would fly to Cuba on Saturday to take part in the investigation.

Associated Press