The Moscow airport blast that killed 35 people may have involved a female suicide bomber from Russia's predominantly Muslim North Caucasus, RIA Novosti quoted a security source as saying.
"The explosion occurred the moment the presumed female suicide bomber opened her bag," the state-run news agency quoted the unnamed security official as saying on Tuesday.
"The terrorist was accompanied by a man. He was standing beside her and (the blast) tore off his head."
Russian investigators said on Monday they had found a head of "Arab appearance" that was initially presumed to have belonged to the suicide bomber.
The unnamed security source said the blast bore the hallmarks of an attack carried out by North Caucasus militants.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"This act of terror followed the classic scheme used by terrorists who come from the North Caucasus," the security official said.
