In a statement, the Prime Minister of the Czech Republic Petr Necas said he was "deeply hit by the tragedy of the gas explosion", the Associated Press reports.
It is not certain what caused the blast in Divadelni Street in the central Prague but it was likely to be a natural gas explosion, police spokesman Tomas Hulan said.
More top news
White House budget officials outlined the information during a telephone call with reporters given on condition of anonymity.
A prison officer is to be charged with gross negligence manslaughter and misconduct in public office in relation to the death of an inmate.
The 2017 Oscars will be remembered as the year the wrong film got the best picture award, but it wasn't the first memorable mix-up.