British Prime Minister Gordon Brown was "appalled" at Monday's suicide blasts in Moscow which killed at least 35 people, a government spokesman said, DPA reported.
The prime minister sent a message of "condolence and support" to Russian President Dmitry Medvedev, the spokesman added.
Two female suicide bombers were believed to have carried out the blasts at two Metro train station in the Russia capital.
Brown's spokesman said the prime minister "was appalled at the scenes coming out of Moscow."
"There can never be any justification for acts of this kind," the premier was quoted as saying.