Three miners died and nine were injured after a strong tremor hit a coal mine in the northeastern Czech Republic on Friday, the private company running the facility said.

"The tremor in the mine occurred at about 900 metres (yards) underground," Marek Sibrt, spokesman for the OKD mining company, told AFP.

"Twelve employees were affected, of whom three have been confirmed dead and the others are being treated for non-life threatening injuries," he said, adding that the tremor could be felt in several cities in the area.

OKD is a unit of the UK-based New World Resources company listed in London, Prague and Warsaw.

The accident occurred in the city of Karvina, about 300 kilometres (190 miles) east of the capital Prague.