Twenty evangelical pastors were among the 110 dead after a plane crash in Cuba left only three survivors.

The Boeing 737 burst into flames shortly after take off from Havana on Friday and crashed near Jose Marti International Airport on the outskirts of the capital. The survivors, all women, are in critical condition, and their progress is being closely followed.

It was the deadliest crash in nearly 30 years, Cuban authorities said.

Prayers following the tragedy were said across the country on Sunday, which marked the second and last day of official mourning for the victims, which included 99 Cuban passengers, three foreign tourists – two Argentines and a Mexican – and two Sahrawi residents in Cuba.

A Cuban Council of Churches member said 20 priests from the evangelical Nazarene Church were among those killed, according to Reuters.

The little-known Mexican airline company, Damojh, had leased the nearly 40-year-old Boeing 737 to Cuban flagship carrier Cubana. The company has come under scrutiny due to allegations of previous safety problems and complaints by former employees.

A pilot who used to work for Damojh was quoted by Mexican newspaper Milenio criticizing the company for lack of adequate maintenance of planes. Damojh declined to comment, while Mexico's Directorate General of Civil Aeronautics said a new audit of the company would be undertaken to ensure it was still 'fulfilling norms.'

Distraught relatives of the victims were told the process of identifying bodies could take up to a month.

'Out of all these corpses, we have 20 identified so far,' Sergio Rabell, head of the National Institute of Forensic Medicine, told the local media on Sunday.