A suicide attack in south-eastern Iran has killed at least 27 members of the Revolutionary Guards, state media say.
The bomber targeted a bus transporting personnel in Sistan-Baluchestan province near the border with Pakistan.
The Sunni Muslim militant group, Jaish al-Adl (Army of Justice), has said it was behind the bombing.
The Revolutionary Guards, set up shortly after the 1979 Islamic Revolution, are a major military, political and economic force in Iran.
What do we know about the attack?
The Revolutionary Guards branch in south-eastern Iran said a unit of its ground forces had been returning from the Pakistan border area on Wednesday when a car filled with explosives blew up beside their bus on the Khash-Zahedan road.
In a statement, it blamed “takfiri terrorists and mercenaries of the intelligence services of hegemonic powers”. “Takfiri” is a term used to describe Sunni extremists who see other Muslims as non-believers.
It did not identify the “hegemonic powers”, but Iran’s foreign minister linked the bombing to a US-led conference on the Middle East taking place in Warsaw, Poland, that will include discussions about Iran’s activities in the region
This is one of the deadliest attacks on the elite forces in years, correspondents say.