An NGO operating clandestinely in Cuba reported this week that the number of political prisoners held on the island doubled between April 2016 and April 2017, following reports of yet another mass arrest of dissidents at an airport in Havana.

The Cuban Commission for Human Rights and National Reconciliation (CCDHRN), an NGO that tracks politically-motivated arrests on the island, revealed this week that, observing its monthly arrest records, there are currently at least 140 known political prisoners in Cuba, up from about 70 such cases a year earlier. The 140 are individuals “convicted of processed [in a court of law] for political reasons or detained under political conditions.”

In its press release, the CCDHRN notes that the prisoners comprising the 140 arrested do not include “the thousands and thousands of innocent people languishing in the nearly 200 prisons, labor camps, and criminal settlements” on the island.

Elizardo Sánchez, the NGO’s director, told the Spain-based publication Diario de Cuba that the Cuban government has “evolved” in how it targets and persecutes anti-communist dissidents. “Now [the repression] is more extended throughout the country and more selective, less ‘noisy,'” he explained. “the regime has increasingly used preventative repression through police threats and other systematic intimidating action.”

The move appears intended to minimize the need for politically-motivated arrests and, thus, keep the eyes of the international community away from the Cuban communist dictatorship.

Police threats and “preventative repression” include acts such as limiting travel within Cuba, “arbitrary confiscation of materials and means of work or profit,” and espionage on individuals who may be involved in anti-government activities.

In April, CCDHRN says Cuba committed a known 475 politically-motivated arrests, 43 more than the month before, and at least 11 physical attacks on political dissidents.

The number of political prisoners and attacks on dissidents in Cuba increased significantly since 2014, when President Barack Obama announced a series of economic concessions to the Raúl Castro regime in exchange for, as Castro said at the time, “nothing at all.” The move has increased profits for the Castro regime that the government has poured into repressing the Cuban people, with no such profits reaching individual Cuban citizens.

The month of May began with a dramatic dissident gang beating and politically-motivated arrest. Daniel Llorente, a man unaffiliated with any political dissident groups, interrupted the nation’s communist May Day celebration by running in front of the parade waving an American flag and shouting “freedom for the Cuban people.”

A mob, later revealed to be plain-clothes State Security officers, beat Llorente and whisked him away. Llorente remained missing for nearly a week before his son, Eliécer Llorente Pérez, found him at an investigative law enforcement center in Havana. Llorente faces charges of “resistance” and “public disorder” for his protest.

“He had everything figured out. My father is an educated man. A few days before he had bought books on the Cold War and the Cuban Missile Crisis,” Llorente Pérez told the Miami Herald about his father this week. He explained that his father chose the American flag as symbol of protest because “he says that’s where there is a true sense of patriotism and family, things that have been lost in Cuba, that all human values have been lost in Cuba.”

Also arrested in May were a group of dissidents organized in Matanzas, a province east of Havana, planning to meet the head of the Cuba Decides democratic movement Rosa María Payá at the Havana airport this week. Iván Hernández Carrillo, Félix Navarro Rodríguez, and his daughters Saylí Navarro were arrested before arriving in Havana around midnight Monday before meeting Payá, who had been traveling the globe raising awareness for the Cuban dissident movement.

The head of the group that Payá’s father, the late Oswaldo Payá, organized, the Christian Liberation Movement (MCL), is among the number of political prisoners. Eduardo Cardet was arrested in November following the death of Fidel Castro, allegedly for expressing discontent with the government-mandated mourning activities for the dictator. According to his wife, Cardet was beaten by a State Security gang in front of his children and detained without prompting. Cardet was sentenced to three years in prison for “attacking an official of the state,” a charge eyewitnesses say has no basis in reality.

Follow Frances Martel on Facebook and Twitter.