Ukraine's SBU security service briefly detained on March 13 four dozen armed participants of a blockade of transport routes to the eastern rebel-held territories in the Donbas region.

"SBU officers spotted a group of people who had arms and other means of destruction amid an anti-sabotage operation in the town of Toretsk, the villages of Scherbynivka and Kurdiumivka" within the demarcated Donbas conflict zone, the Anti-Terrorism Centre's headquarters in Kyiv told Interfax news agency. "They refused to be disarmed by police, which was the ground for the detention of 43 people."

A group of pro-government veterans of the Donbas conflict announced in December their intention to block trade with coal-producing eastern parts of the country, controlled by Russia-backed rebels, in protest at continued trade with the region. The rail blockade led to acute shortages of anthracite coking coal, which accounts for one third of all electricity generated in the country.

Earlier, Ukrainian Interior Minister Arsen Avakov urged the government to use force to lift the blockade.

President Petro Poroshenko accused the protesters of inflicting broad damage to the state, citing harm done to the population and also key industries like metallurgy by the fuel shortages.

The arrest of the activists triggered protests from nationalists and blockade activists in several cities, including Kyiv’s famous Maidan square, where huge crowds gathered in 2013-2014 before the former regime of President Viktor Yanukovych was toppled. Another Maidan protest was planned for the evening of March 14, as activists remain unconvinced by the government's decision to halt the blockade because of the economic damage it's doing to the country as a whole.

"The month-long conflict between the government and the blockade activists is intensifying," Zenon Zawada at Kyiv-based brokerage Concorde Capital wrote in a research note on March 14. "Yet the blockade is still popular with the public, which is also highly dissatisfied with the government’s handling of the war."

On February 16, Poroshenko authorised orders of the National Security and Defense Council (NSDC) enabling the interior ministry and SBU security service to "neutralise threats" to the country's energy security and boost protection of gas- and power-supply facilities and transport infrastructure in the region.

According to Interfax, the roadblock of the blockade at the Kryvy Torets railway station in Scherbynivka was reportedly taken over by SBU officers and members of the Ukrainian police's KORD special weapons and tactics force.

"Information about the storming of the checkpoint has been confirmed. The facility in Kryvy Torets has been taken over by the SBU and KORD troops," organisers of the blockade said on March 13. "The headquarters is trying to defend other checkpoints and seeking the release of blockade activists who have been unlawfully remanded in custody."

On March 14, the National Police's main department in the Donetsk region specified that forty-five participants of the blockade were detained near the Kryvy Torets railway station, and shortly they have been released.

"Four [of them] were registered owners of firearms and six who had previous criminal records," chief of the department in the Donetsk region Viacheslav Abroskin wrote on his Facebook page. "As of today's morning, all of them had been released. None of them has any injury."

Later the same day, Ukrainian Prosecutor General Yuriy Lutsenko said there was no violation of law by operatives who detained the armed participants of the blockade. "So far there has been no inidcation of violations of law committed by law enforcers during the detention of these people and the seizure of their arms," Lutsenko told journalists in Kyiv.