Felix Yuniel Llerena Lopez, 20, left Cuba for the first time and attended a meeting arranged by Christian Solidarity Worldwide (CSW) in Washington to raise concerns about continued violations of religious freedom in Cuba.
The charity claims Lopez was interrogated by state security agents upon arrival at the Abel Santamaria International Airport in Santa Clara on April 27. The next day, he was detained by state security, interrogated, threatened and forced to sign a pre-arrest warrant for public disorder.
Lopez said that he was questioned aggressively by two high ranking state security officers, who had detailed information about what he was doing abroad.
They told him: "This is a country town; the people here don't know anything about human rights and if one of these country peasants is made to believe that you are going to commit a terrorist act, he is going to cut you open with a machete, and later you won't be able to say that we sent him."
His mother, Mileidis Lopez Sosa, was also interrogated despite not accompanying her son on the trip.
Lopez is the central region coordinator for the Patmos Institute, an independent civil society organisation which promotes freedom of religion or belief and inter-religious dialogue and cooperation.
He visited Washington, DC in April as part of a delegation that included Apostolic Movement Pastor Yiorvis Bravo Denis, Baptist church leaders Reverend Mario Felix Lleonart Barroso and Yoaxis Marcheco Suarez and Baptist theologian and former political prisoner Raudel Garcia Bringas.
CSW's Chief Executive, Mervyn Thomas said in a press release: "We are extremely concerned about the government's treatment of Felix Yuniel Llerena Lopez.
"Public accusations linking him to terrorism are not only preposterous and unfounded, but also put his family in danger.
"We call on the Cuban government to cease its harassment of Felix and to turn its attention to addressing its ongoing violations of freedom of religion or belief as a matter of urgency. We also urge the international community to closely monitor this situation."