Havana — At morgues and in church services, tearful Cubans on Sunday mourned loved ones who died in the country's worst air disaster in three decades.Island authorities said they have identified 20 bodies and recovered all human remains from the field next to Havana's international airport where a passenger jet crashed on Friday, killing 110 people.Maidi Charchabal wept and held a photograph of her son Daniel Terrero, who would have turned 22 years old Sunday, as she waited at Havana's Institute of Legal Medicine for experts to complete their identification of his body."We are here today so that, even if only in consolation, they hand over his body to us, so we can ... be able to be with him on his birthday," Charchabal told The Associated Press."We are very pained by this loss," she added.Cuba's chief forensics official, Jorge Gonzalez, said all families had been contacted and asked to provide blood and objects such as photographs and toothbrushes that could be used in identifications.He said the number of bodies recovered by authorities matches the tally of those on board, accounting for three Cuban women were the only survivors and who were hospitalized in serious condition, so it is believed none are unaccounted for.Gonzalez said many of the bodies were affected by the trauma of the crash, the flames and the heat, and the identification process could take at least 30 days."We are in a hurry, but we will work with all the carefulness that this requires," said Gonzalez, a specialist who led the search and identification of the remains of revolutionary guerrilla Ernesto "Che" Guevara in Bolivia.The Boeing 737 belonging to a Mexican charter company and hired by Cuban state-run airline Cubana de Aviacion veered sharply shortly after takeoff from Havana on Friday afternoon and crashed in a fireball in a cassava field. Its destination had been the eastern Cuban city of Holguin.It was carrying 107 passengers — mostly Cubans and also five foreigners — and a six-person flight crew from Mexico. Some family members of the Mexican victims arrived in Cuba late Saturday to assist in the identifications.Also Sunday, evangelical churches held prayer services for 20 pastors — 10 married couples — from the Nazarene Church of Holguin who died while returning home after several days of a spiritual retreat in the capital."They were consecrated pastors who during the entire retreat expressed their pleasure," said Rev. Pedro Urgelles, their host in Havana. "We believe in eternal life and they have gotten there before us."At the Evangelical League Temple, pastor Fernando Rodriguez projected photos of some of the deceased clerics onto a wall for parishioners and led a prayer."Although we may not comprehend why this happened, the believer knows that the Lord is sovereign," he said to responses of "hallelujah" from the flock.Cuba has declared two days of national mourning over the disaster, whose cause is under investigation.