Russia’s federal security service, the FSB, is cracking down on Ukrainian activists in Crimea. Late last week, it announced the arrest of four people in its newest jurisdiction for allegedly planning to blow up various targets, including a Lenin statue.

VICE News interviewed one of the suspects, an activist named Gennady Afanasiev, shortly after the March referendum that Russia used to justify its annexation of the Crimean peninsula from Ukraine.

We had been in touch with Afanasiev in the regional capital of Simferopol to find out where and when pro-Ukraine protests were going to be held. Even as Russian troops tightened their grip on the Ukrainian province, he was one of a few organizers of the rallies who wasn’t afraid to continue his activism.

But because things had gotten so dangerous for supporters of Ukraine by the time we interviewed Afanasiev on camera, he had taken to wearing clothes in the colors of the Russian flag. He told us that he had stopped meeting with fellow activists as a precaution.

“We don’t meet up anymore,” Afanasiev said. “Someone could rat us out, we could get attacked, they could say we’re extremists or terrorists.”

Afanasiev appears in a segment of this video beginning at the 6:30 mark.

And it seems that’s exactly what happened. In a press release issued on Friday, the FSB announced that it had thwarted a terrorist attack that targeted the “Eternal Flame memorial and the V. I. Lenin monument in the city of Simferopol early on May 9, as well as an arson attack against the office of the Russian Community of Crimea and the representative office of the United Russia party” — Russian President Vladimir Putin’s political party.

The FSB said that it found homemade bombs and nationalist literature at the suspects’ homes.

Among the other activists arrested with Afanasiev was Oleh Sentsov, an award-winning film director who supported the protests that toppled Ukraine’s former president Viktor Yanukovych and opposed Crimea’s annexation to Russia.

In a statement issued from Berlin, the European Film Academy called for Sentsov’s immediate release.

“The EFA Board cannot tolerate it when people are persecuted for political reasons and wishes to underline its firm belief in the free expression of opinion as an essential and basic value of any democratic society,” the statement in support of Sentsov said.

According to the FSB, Afanasiev, Sentsov, and the two other activists, Oleksy Chyrny and Oleksandr Kolchenko, are terrorists.

“The suspects have confessed to being part of Right Sector and to organizing terrorist acts on the territory of Crimea with the aim of destabilizing the social and political situation on the peninsula,” the Russian security service claimed in its statement. Right Sector, the Ukrainian nationalist group, has denied that the four were members.

Russia has repeatedly blamed ultra nationalists from Right Sector for planning attacks against Russian-speakers in Ukraine, calling them fascists and claiming that their members have overrun the country. The organization has less influence in Ukraine than is portrayed by the Russian authorities, however. Right Sector leader Dmytro Yarosh received less than one percent of the vote in last week’s presidential election, which brought the centrist billionaire Petro Poroshenko to power.

Ukrainian Foreign Minister Andrii Deshchytsia told VICE News that his ministry had formally requested that Russia allow Ukrainian consular officials to meet the suspects in Moscow, where they are being held.

“We are still waiting for their reply,” Deshchytsia said. “So far we have not been shown any real evidence that would confirm the charges that they are being accused of.”

Asked if he was considering an exchange of Russian citizens in Ukrainian custody for the Crimean activists, Deshchytsia replied that his ministry hadn’t discussed whether to do so.

“I think the first thing is to follow through on the legal procedures and await a response from the Russian side,” he said. “But we will also raise the issue on the international arena because this is a violation of human rights.”

Ukrainian human rights lawyer Yevgenia Zakrevskaya told VICE News that the Ukrainian government was not doing enough to secure the release of its citizens.

“These people arrested in Crimea are subject to the Geneva Conventions,” she said. “Their legal status is equal to that of prisoners of war and the Ukrainian government should behave itself accordingly. These are not criminals arrested for breaking Russian laws. They are Ukrainian citizens detained on Ukrainian occupied territory and as such should be subject to a prisoner exchange instead of facing 20 years in a Russian prison on terrorism charges.”