By Agence France-Presse
Cuban state media reported that three women had been pulled alive from the mangled wreckage and were in critical condition in hospital.
They were the only known survivors from the nearly 40-year-old Boeing 737, operated by Cubana de Aviacion. It crashed into a field close to a wooded area near Jose Marti airport, sending a thick column of acrid smoke into the air.
The 110 people aboard included six Mexican crew, said the Mexico-based company that leased the plane, Global Air, also known as Aerolineas Damojh.
Two victims were Argentine, the country's foreign ministry said. Most of the others were Cuban, according to state media.
The plane -- carrying 104 passengers -- was almost completely destroyed in the crash and subsequent fire. Firefighters raced to the scene along with a fleet of ambulances to put out the blaze, as emergency personnel combed through the wreckage.
What appeared to be one of the wings of the plane was wedged among scorched tree trunks, but the main fuselage was almost entirely destroyed.
Cuba's President Miguel Diaz-Canel, who visited the scene, said an investigation has been opened into the disaster, and that its findings would be made public as soon as possible. A press conference was scheduled for 1900 GMT on Saturday.
The 58-year-old president, who succeeded Raul Castro as the communist island's leader only last month, appeared aghast as he surveyed the recovery efforts, wearing a short-sleeved green shirt and surrounded by officials.
He said an investigation into the cause of the accident was underway.
Cuba declared two days of national mourning.
Raul Castro sent condolences to families of the victims of the "catastrophic accident," a statement read, as Russian President Vladimir Putin and a string of Latin American leaders also expressed sympathy.
'The explosion shook everything'
Airport sources said the plane took off at 12:08 pm (1608 GMT) heading for the eastern city of Holguin, 670 kilometers (415 miles) away.
From the supermarket where he works near the airport, Jose Luis, 49, said he could see the plane taking off before it banked and plunged to the ground.
"I saw it taking off. All of a sudden, it made a turn, and went down. We were all amazed," he said.
Yasniel Diaz, a 21-year-old musician, said the pilot appeared to attempt an emergency landing, but crashed instead.
"The explosion shook everything," he said.
"I started running, I was so afraid."
Images from Cuban television showed rescue workers at the scene removing what appeared to be a survivor on a stretcher as rain began to fall.
Global Air said the plane was flying with a crew of six Mexicans -- the pilot, co-pilot, three flight attendants and a maintenance technician.
In Mexico City, anguished relatives and colleagues of the crew gathered outside the company's offices demanding information -- some of them hugging and crying.
"I was friends with the captain, with the co-pilot, with the head flight attendant," said a former Global Air employee, 44-year-old Ana Marlene Covarrubias.
"When I heard the news on the phone, I thought it was one of those jokes people play," she told AFP.
Mexico said it had sent two civil aviation specialists to help in the investigation.
The Mexican communications and transportation ministry said the plane was built in 1979. Global Air had the necessary permits to lease it, and had passed inspections in November last year, it said.
The company, formed in 1990, had a fleet of three planes, all Boeing 737s.
Prior to Friday's crash, Cuba's most recent air accident occurred in April 2017, when eight military personnel died when a Russian-made AN-26 transport aircraft went down in western Cuba.
The country's last major airline disaster was in November 2010 when a Cuban Aerocaribbean jet crashed on a flight from Santiago de Cuba to Havana, killing all 68 people on board, including 28 foreigners.