The gunmen were stopped at the entrance of the city of Energodar, near Zaporizhia Nuclear Power Plant, the facility's press service said in a statement on its website.

The power plant’s authorities said the incident did not affect the station’s operations. However, security at the plant and throughout Energodar has been heightened.

Several cars full of men who introduced themselves as members of the notorious neo-Nazi group Right Sector were stopped at a checkpoint near Energodar, Ukraine’s Komsomolskaya Pravda newspaper reported. The men were wearing masks, had guns, and said that they were heading to “protect the nuclear power plant and the city from possible seizures,” according to the paper.

“We moved out to protect the city, but we were stopped and circled by police,” a Right Sector member said.

Local police said they confiscated the men’s weapons and launched a criminal investigation.

Footage posted on Svoboda TV's YouTube account on Thursday – allegedly shot during the attempted break-in – shows a group of masked men preparing to enter Energodar.

In the footage, the men say they are members of the Right Sector in Zaporizhia (Zaporozhye) region, adding that they came to protect Energodar from activists who wanted to “hoist Russian flags” in the city.

“The Right Sector got hold of information that pro-Russian activists are preparing to change [Ukrainian] flags to Russian at the check points of Energodar city. The Right Sector moved forward to prevent this,” one man says.

However, on its official website, the Right Sector denied that its men wanted to seize the station.

Zaporizhia Nuclear Power Plant is the largest nuclear power plant (NPP) not only in Ukraine, but also in Europe, according to the operator of Ukrainian NPPs. It is situated in the steppe zone of Ukraine, on the bank of the Kakhovka water reservoir.

The plant generates 40-42 billion kWh per year, which accounts for one-fifth of the average annual electricity production in Ukraine and almost 47 percent of electricity generated at Ukrainian nuclear power plants.

NTJ/HH