Nine soldiers were injured in an explosion on Monday on a Czech military site used to train Ukrainian troops, the army and a hospital said.

Two soldiers with moderate injuries were taken by helicopter to the University Hospital in the nearby city of Olomouc, some 200 kilometres (125 miles) east of the capital Prague, said the hospital's spokesman Adam Fritscher.

"Six were transported to an army hospital in Olomouc by ambulance vans and one was treated on the site," he told AFP.

Libava, just east of Olomouc, is where the Czech army has been training Ukrainian soldiers since late 2022, following the Russian invasion of Ukraine in February of that year.

But military police spokeswoman Katerina Mlynkova told AFP the injured "were not foreigners".

The army said on X that "unspecified ammunition had exploded" without giving any further details.