Czech police say they have carried out one of the biggest seizures of illegal explosives and other dangerous substances in the country's history.More than 100kg (220lb) of various explosives were seized, said spokesman Pavel Hantak.
Four men, who were allegedly planning to sell the explosives on the black market, were arrested.
Police launched a massive operation following rumours that large amounts of explosives were being sold illegally.
Three raids took place simultaneously in the regions of Pardubice, Hradec Kralove and Central Bohemia.
It happened last week but has only now been publicised.
The explosives included Semtex, a plastic explosive used in commercial blasting and demolitions, and over 1,000 detonators.
Investigators also seized close to 150kg of materials that are used to make explosives and 50kg of dangerous poisons and toxic materials.
The arrested men, aged between 26 and 73 years, face up to eight years in prison if convicted.