An attacker shot and killed at least six people and seriously injured two in a hospital waiting room, in the northeast Czech city of Ostrava on Tuesday.
The alleged gunman killed himself with a shot to the head, police said, having found the suspect dead in a car they had been looking for.
People were evacuated from the hospital and security has been increased across the country.
Prime Minister Andrej Babis told Czech public television the attacker opened fire at people’s heads from close range, Babis said.
“It’s something we’re not used to in our country,” said Babis, a populist billionaire. “I absolutely don’t understand the motive of this young man.”
President Milos Zeman also sent condolences. “I’m with you in my heart, I’m thinking of you in these tragic hours,” he said in a tweet sent out by his spokesman.
Shooting incidents are rare in the Czech Republic. The last major attack took place in February 2015, when a man killed eight people in a restaurant in Uhersky Brod before turning the gun on himself.
That attack in the country’s east helped prompt efforts by populist politicians to challenge the EU’s efforts to place heavier restrictions on personal firearms. However, the European Court of Justice threw out the challenge earlier this month.
Czech journalist Teodor Marjanovic told Al Jazeera: “People are in shock, shootings happen very rarely in this country. There’s a huge police operation right now in the city.”
The shooting in Ostrava, a steel hub located about 300 kilometres (185 miles) east of Prague and 15km (nine miles) from the Polish border, was the worst shooting since the 2015 incident.
Hospital director Jiri Havrlant told a televised briefing that five victims died in the attack and one died in surgery. No medics were hurt, he said.
“Until now we thought that the US-style shootings we see every day would not happen here. But now we have it,” former Czech military intelligence chief Andor Sandor told Al Jazeera.
He noted, however, that the Czech Republic was ranked among the top 10 safest countries in the world, saying he does not expect frequent shooting incidents.
Sandor, who praised the police for a swift response, said the security alert around the country was likely to be relaxed soon, as police establish for certain that the suspect acted alone.
Populists have been quick to use the tragedy to revive their calls for easing gun control.
Radek Koten from the far-right Freedom and Direct Democracy party (SPD) claimed: “If there was a decent, armed person in the waiting room, he could have eliminated the perpetrator.”
The director of the Moravian-Silesian Police Tomas Kuzel said the gun the suspect used was not legally registered.
Sandor dismissed the suggestion that Czech people need semi-automatic rifles to protect themselves,
“You need special training and a special mindset to react quickly and kill an attacker. I don’t believe being armed would have saved anyone,” he said.
With reporting by Tim Gosling in Prague.