HAVANA (Reuters) - Communist-ruled Cuba on Wednesday said it had foiled a serious plot aiming to destabilize the country by preventing the chief of the Organization of American States traveling to the island to attend an award ceremony organized by dissidents.

Organization of American States (OAS) Secretary-General Luis Almagro addresses the audience during an official visit to Honduras, in Tegucigalpa, January 17, 2017. REUTERS/Jorge Cabrera

The opposition group, which the government called “anti-Cuban and illegal,” had invited OAS Secretary General Luis Almagro to Havana to honor him for shining a light on violations of human rights in the Americas.

Cuba, which views the Washington-based OAS as an imperialist instrument of the United States despite its fledgling detente with its Cold War foe, denied Almagro and other international invitees visas and issued a blistering statement.

The incident comes at an awkward time as U.S. President Donald Trump considers whether to continue normalizing relations with the Caribbean island.

“The plan ... consisted of mounting in Havana an open and serious provocation against the Cuban government, generating internal instability, damaging the country’s international reputation,” the statement by the foreign ministry read.

The ministry accused Almagro of “an ambition agenda of auto promotion with attacks against progressive governments like those of Venezuela, Bolivia and Ecuador.”

In a letter to the dissidents, Almagro said he had assured the Cuban authorities he did not have an anti-Cuban agenda.

The OAS’s only interest was to “help move Cuba closer to the values and principles upheld by the organization in relation to democracy and human rights,” he said.

Cuba had earlier prevented other international invitees, including a former Chilean minister and an ex-president of Mexico, from traveling to Cuba to attend the award ceremony, stoking tensions across Latin America.

Chile said it was recalling its ambassador to Cuba for consultation while Mexico’s foreign ministry said on its Twitter account that it “regretted” Cuba’s decision.

The Cuban foreign ministry defended its move as “impeccable act of transparency,” saying it had contacted the countries from which invitees were traveling to inform them of the plot, hoping they could be dissuaded from traveling.

“There was no lack of declarations by defenders of the false persecuted, allies of past dictatorships and unemployed politicians willing to ally themselves with vulgar mercenaries in the service of foreign interests,” the ministry said.

The dissident group that had organized the award ceremony is led by the daughter of late democracy activist Oswaldo Paya, who died in a 2012 car accident. Rosa Maria Paya accuses the Cuban government of causing the crash, a charge it denies.

Paya went ahead with the ceremony on Wednesday in the Paya family home in Havana as planned, although she said she would keep his prize until he could pick it up in person.

That looks unlikely to happen soon. In its statement on the events, Cuba denounced a recent neo-liberal, imperialist offensive against certain Latin American countries that had plunged millions back into poverty.

“Where has the OAS been, that has always kept a complicit silence facing these realities?” the ministry asked, reiterating that Cuba would never rejoin the organization.

Fidel Castro, a leading Cold War figure who built a communist state on the doorstep of the United States and defied U.S. attempts to topple him, died in November at the age of 90, eight years after handing the presidency over to his younger brother, Raul.