(CNN) -- Fifteen people were killed and four others seriously hurt when a tourist bus crashed into a crowd in eastern Bulgaria, the country's Interior Ministry said Thursday.
The crash happened about 9:30 a.m. (2:30 a.m. ET) near the town of Jambol, according to preliminary information from the ministry.
A 60-year-old local man was driving the bus when it crashed into a crowd that had gathered for a folklore meeting on a mountain road, a ministry press officer said.
Of the 15 casualties, 10 were women and five were men, the spokesman said. None was thought to have been on the bus.
Four people suffered life-threatening injuries and were being treated at a hospital, the spokesman said.
No children or foreigners were among the dead or injured, the Bulgarian Embassy in London said.
Bulgaria's prime minister and interior minister were on their way to the crash site, the embassy said, and the government declared a national day of mourning on Friday.
CNN's Nicola Goulding contributed to this report.