An explosion has torn through a bus in southern Russia, in what the authorities say was a bomb attack, killing at least five people.
Investigators say another 20 were injured. They believe it was the work of a female suicide bomber, a rebel chief’s wife who had recently converted to Islam.
It happened in the city of Volgograd, formerly known as Stalingrad. There has been no claim of responsibility.
Several hundred kilometres to the south, Islamist insurgents have carried out attacks in Russia’s mostly Muslim North Caucasus.
If the bus blast is confirmed as terrorism, it makes it the deadliest attack outside the region in nearly three years.
Initial reports spoke of a gas explosion but the authorities then launched a terrorism inquiry.