PRAGUE (AFP) - A former Czech nurse was indicted with six counts of murder over allegations she poisoned patients with massive doses of potassium during the past four years, Czech media reported Thursday.

Identified by media as 50-year-old Vera Maresova, the nurse was originally charged in August for a single murder alleged to have been committed in June.

But justice officials expanded the indictment after it emerged that five other patients under her care also died under suspicious circumstances.

"The suspect was charged with five additional counts and is now being prosecuted in connection with six counts of murder," prosecutor Frantisek Stibor told the Czech Television public broadcaster.

The nurse was taken into police custody on Thursday over "concerns she could escape and hide," judge Jan Tichy said, quoted by the Czech news agency CTK.

If convicted, Maresova faces life behind bars for the deaths at a hospital in Rumburk, a town about 100km north of the capital Prague.

Last month, Italian media reported that a local nurse who took photographs of herself with dead patients had been accused of murdering one of them using potassium and is suspected of killing dozens of others in the same way.

Potassium can stop the heart and is one of the components used in the lethal injection given to death row inmates in the United States.