PRAGUE (Reuters) - A teenaged attacker killed two women with a knife in a shopping centre in the Czech city of Hradec Kralove on Thursday before being detained shortly afterwards, police said.

Police were investigating the motive for the attack in the city 110 km (68 miles) east of Prague.

"Although we were on the scene within a few minutes of the report, both victims suffered injuries so serious that they could not be saved despite all efforts of responders," the police said in a post on X.

A police spokesperson told the Novinky.cz online news website the attack took place in a store at the outdoor shopping centre. The victims were employees at the shop.

The suspected male attacker, a 16-year-old Czech citizen, was detained 10 minutes after the incident less than a kilometre away, the spokesperson said, adding a knife with a blade about 20 centimetres (8 inches) long was found nearby.

"The attacker's motive is still unclear," police said on X. "However, there is nothing to suggest that this was a terrorist attack. The information that we have at the moment, which may still change, suggests that the selection of victims was random."

Police had initially said the victims were wounded in the attack, before later reporting they had died from the injuries.

A paramedic responding to the scene told Novinky.cz that resuscitation efforts lasted around 40 minutes.

(Reporting by Jason Hovet in Prague and Anna Magdalena Lubowicka in Gdansk; Editing by Bernadette Baum, William Maclean)