A powerful explosion has damaged a building in the centre of the Czech capital Prague, the Associated Press reports.
Police spokesman Tomas Hulan said it is not immediately clear what caused the blast and it is believed some people are buried in the rubble.
At least 13 people have been injured, fire service spokeswoman Pavlina Adamcova said.
Windows in buildings located hundreds of metres from the blast were shattered, including some in the nearby National Theatre.
Presiding judge Tomas Kubec ruled that Randy Blythe's actions did not constitute the crime of causing an injury leading to death.
"We did not find criminal responsibility in the actions of the defendant," he said. "We found moral responsibility. There has been the death of a young man who had not been guilty of anything."
Kubec said the concert promoters were ultimately to blame for failing to prevent fans from clambering onto the stage.
"We reached the conclusion that there was a serious fault on the side of the promoter and organiser of the concert."
Prosecutors immediately appealed against the acquittal, meaning that the case will be reviewed by the Czech High Court.
Randy Blythe, singer of US metal band Lamb of God, was today acquitted of charges of causing the death of a fan.
He posted the above photograph shortly after the verdict of the court in Prague, along with the following message:
"I have been found not guilty & acquitted of all charges against me. I am a free man. This photo was taken by my friend@aceyslade- it says it all.
"Please remember the family of Daniel Nosek in your thoughts & prayers in this difficult time. I only wish for them peace. Thank you for your support- Randy."
A Czech court has acquitted the frontman of US heavy metal band Lamb of God, Randy Blythe, of charges he caused the death of a fan at a concert in Prague three years ago.
The prosecution had accused Blythe, 42, of causing the death of the 19-year old fan by pushing him off the stage at a 2010 concert.
Leftist former prime minister Milos Zeman won the Czech Republic's first direct presidential election, partial results showed today.
Mr Zeman, 68, was leading by 55.8 to 44.2 per cent over Foreign Minister Karel Schwarzenberg, a prince from a centuries-old aristocratic family, results from 93.75 percent of voting districts showed.
Czech President Vaclav Klaus has been shot with a replica pistol during a walkout in the north of the country. He suffered minor bruising in the attack.
Czech Prime Minister Petr Necas has said that his government mandated him not to accept EU proposals for deeper integration at a summit on Thursday and Friday, specifically mentioning plans to create a banking union.
He said: "The mandate orders me not to accept the proposals that have been in circulated in the media so far...
"Some proposals like the banking union could have extremely damaging impact on the Czech economy."