Russia's FSB security service said Tuesday it had seized dozens of kilos of explosives sent from Ukraine concealed in Orthodox Christian religious icons that transited through the European Union.

The seizure followed an inspection of cargo in the northwestern Pskov region near the Latvian border, the FSB said in a statement.

It said this was "part of the cross-border traffic of explosives from Ukraine through the European Union", adding that the cargo had passed through Romania, Hungary, Slovakia, Poland, Lithuania and Latvia.

The seized cargo comprised 70 kilos (154 pounds) of home-made explosives and explosive devices "hidden in icons and ready for use".

One person was arrested, it said, adding that it would seek to track down all those involved, including foreigners, who would then face legal proceedings in Russia.