Anti-nuclear protesters broke into a construction site for a nuclear reactor on 26 April, choosing the 30th anniversary of the Chernobyl disaster for their demonstration. Police estimated that close to 50 protesters gathered near the Fennovoima site, northern Finland, and around 40 were detained by authorities.

One group broke into the site, while others lay down on the road leading to the site's entrance, police said. Fennovoima's Heli Haikola said around 10 protesters entered the site but work was able to continue.

The plant is to be supplied by Russia's state-owned nuclear firm Rosatom. Venla Simonen, from the Stop Fennovoima protest group, said they wanted to remind people that the Chernobyl plant was built by Rosatom's predecessor.

Rosatom was the successor to the Soviet nuclear industry and builds nuclear plants in Russia and around the world. Its website cites safety as the highest priority in its work. The Chernobyl disaster increased radiation levels in Finland, putting nuclear Finnish plant projects on ice for a decade.

26 April marked the 30th anniversary of the Chernobyl disaster in then-Soviet Ukraine, caused by a botched safety test at the atomic plant's fourth reactor, sending clouds of nuclear material across much of Europe.

This latest project has raised concerns and caused resistance by many Finns as the plant is set to forge deeper energy ties between EU state Finland and its former ruler, Russia, despite East-West tensions over the Ukraine crisis. Fennovoima's proposed 1,200-megawatt nuclear reactor would be Finland's sixth nuclear plant and is due to start operation in 2024.