Russia has called for international solidarity in the fight against "terrorists" after two deadly suicide bombings in the southern city of Volgograd.
In a statement, the Foreign Ministry said: "We will not retreat and will continue our consistent fight against an insidious enemy that can only be defeated together."
It did not place direct blame on any particular group for the attacks but said they came against a backdrop of threats from militants.
They include Doku Umarov, leader of an Islamist insurgency in the North Caucasus who has called on fighters to prevent Russia holding the Winter Olympics in February.
More top news
Bitterly cold with clear skies in the east & wintry, wet weather in the west
The Big Sick star Kumail Nanjiani and Black-ish star Tracee Ellis Ross announced the 91st Academy Awards.
A recruitment advert has been dropped by the College of Police following complaints from frontline officers.