The defence ministry in Moscow says a Russian fighter jet accidentally bombed the city of Belgorod near the border with Ukraine.
Regional Governor Vyacheslav Gladkov said the blast had left a huge crater about 20 metres (60 ft) wide in the city centre.
Three people were injured and several buildings were damaged, he said. One apartment block was evacuated.
A Su-34 fighter-bomber jet accidentally released the bomb, the ministry said.
The defence ministry said the bomb fell at 22:15 local time (19:15 GMT) on Thursday. There was no explanation for the bombing other than what it described as an “abnormal descent of aviation ammunition”.
The bomb landed at an intersection of two roads not far from the city centre and next to residential buildings.
Video has emerged on social media of the bomb causing an initial blast and some damage, as cars continue to stream along Prospekt Vatutina. Then, 18 seconds later the bomb detonates, blowing up a section of the road, catching one of the cars as it passes.
Two women were taken to hospital for treatment and a nine-storey apartment block was evacuated because of potential structural damage, Mr Gladkov said.
An investigation is under way.
bbc
