Hopes that a group of young independent Cuban cultural figures could hold a rare dialogue with the authorities about freedom of expression have been dashed after the communist government vetoed some of them from attending, accusing them of being US puppets.

“We support dialogue, but with no preconditions or blackmailing,” said President Miguel Díaz-Canel on Twitter. “We will not legitimise those who are helped by the US to damage Cuba.”

The Havana government had promised the talks while negotiating an end to an unusual public demonstration by around 300 mainly young artists, writers and supporters outside the Culture Ministry on November 27. That group was protesting at a crackdown by the authorities on the San Isidro Movement of dissident performance artists and activists, which often stages provocative acts that run foul of the authorities. The dissent comes at a time of severe economic crisis, with shortages of food and fuel exacerbated by tightened US sanctions.

Representatives of what has been dubbed “The Revolution of Applause” said that no sooner had they returned home from the protest than state media began branding them part of a US plot. They added that security forces have continued to harass and temporarily detain activists.

The Cuban government said political agitators aligned with the US had hijacked what was supposed to be a discussion of how to improve access for young artists.

“We will not meet with people who have direct contact and receive funding, logistical support, and propaganda support from the United States government and its officials. Nor with media financed by US federal agencies,” the Culture Ministry said on Friday after receiving from the artists a list of non-negotiable participants for the dialogue that included movement members and independent media.

Nevertheless, the debate over freedom of expression at a time of tight US sanctions continues to reverberate throughout Cuba and the diaspora beyond, fuelled by social media, especially among the youth.Paul Hare, a former UK ambassador to Cuba who lectures at Boston University’s Pardee School of Global Studies, said there had long been an undercurrent of intellectuals and artists who have reacted to repressive measures but stopped short of forming a wider political movement.“Now the protesters have for the first time in such circumstances access to social media,” he said. “This is now being exploited by other elements who see that a protest can gain momentum. The government therefore now has to deal with wider expressions of frustration and so far has fallen back on the old scapegoat of US imperialism.”

The artists and their supporters have been unable so far to return to the streets to press their case, though they have kept the issue of freedom of expression alive on social media.They have also launched a petition with their original demands. It now begins by stating there can be no freedom of artistic expression without political freedom and calls for “the right to political freedom that allows us to build a truly inclusive and democratic nation,” a non-starter in the communist-run Caribbean island.The sit-in outside the Culture Ministry last month ended only after a four-hour discussion between officials and representatives of the crowd which applauded every 15 minutes to show its support.The negotiators emerged with a deal for an urgent review of the case of an imprisoned rapper, ongoing talks over their complaints about policy in various sectors of the arts to begin within the week and a guarantee that independent artists would not be harassed by the police.

A few hours later the government called in the top US diplomat on the island, charge de affairs Timothy Zúñiga-Brown, for a scolding over “grave interference in Cuba’s internal affairs”. State television also ran a 90-minute special attacking the rapper and other dissident artists, broadcasting footage of them with US diplomats and Miami exiles.

President Miguel Díaz-Canel then appeared at a youth rally supporting the government where he evoked Fidel Castro’s famous statement to intellectuals in 1961, “within the Revolution everything, outside the Revolution nothing” and charged that an attempted soft coup was under way.