Four people, including two children, have died and more than 100 were injured on Thursday in southern Poland when a thunderstorm hit the Tatra mountain range, Prime Minister Mateusz Morawiecki said.
The victims were tourists climbing Giewont, a 1,898-metre high mountain where a 15-metre steel cross — believed to attract lightning — is installed.
"Nobody expected such a sudden storm to break out and from our human point of view it was something which was impossible to predict," Morawiecki said after attending an emergency meeting in the nearby town of Zakopane.
He also thanked the emergency services, tourists and Zakopane residents "who selflessly joined in to help."
Six helicopters from the country's LPR Medical Air Rescue service, the police and the mountain rescue service, TOPR, were deployed as part of the rescue, the local government said in a statement.
A fifth person also died on the Slovak side of the mountain, the country's mountain rescue service said. They added that several tourists had also been injured by lightning, including one who lost consciousness and was temporarily paralysed.
Zakopane Mayor Leszek Dorula declared the city would be in mourning from August 23-25 with state and city flags at half-mast.
"I unite in pain with the families of the victims and all the victims," he said in a statement, calling on Zakopane residents "to pray for them."
President Andrzej Duda sent his "sympathies to everyone affected by the disaster."