BOGOTA, July 30 (Reuters) - Colombia called on Haiti on Friday to guarantee the legal and medical rights of 18 Colombians detained on the Caribbean island for alleged participation in the assassination of President Jovenel Moise. Many questions remain over who was behind the assassination this month and how the killers gained access to the president"s home. Haitian officials blamed a squad of mostly Colombian mercenaries, three of whom were killed by police. A top Moise security official was arrested on suspicion of involvement on Tuesday. read more Families and colleagues of the detained men have told journalists they were hired to act as bodyguards, not assassins, while Colombia"s president has said some knew of the plot. Colombia"s Vice-President and Foreign Minister Marta Lucia Ramirez asked for legal representation and medical care for the detained Colombians in a letter to Haiti"s ambassador, the Foreign Ministry said in a statement. "Through a letter, sent to the ambassador in Colombia, Jean Mary Exil, the vice-president expressed her worry after the visit carried out by the Colombian consular mission, which found irregularities in the detention and assistance to the citizens supposedly involved with the assassination," the ministry said. The Colombians had not been assigned legal defenders to guarantee due process in violation of the Vienna Convention, it said, adding that some had sustained injuries when they were arrested and had received no medical attention. "I remind your government that it has a moral and legal obligation to protect detainees," Ramirez wrote in the letter. Colombia"s ambassador to the Dominican Republic, which shares the island of Hispaniola with Haiti, would visit the detained men at least twice a week if his diplomatic credentials were accepted by Haiti, it added. The Haitian embassy in Bogota did not immediately respond to a request for comment. Haiti, which was already struggling with political paralysis, economic malaise and gang-fueled violence, was pushed deeper into turmoil by the killing of Moise. Haiti"s new Prime Minister Ariel Henry said on Wednesday that the government planned to create conditions to hold elections as swiftly as possible. read more