"The only answer to these barbarous terrorist actions must be further growth and deepening of joint efforts in the fight with this threat," the message said.
The Kremlin chief of staff, Dmitri Medvedev delivered the message to the United States while he is on a working visit there.
On February 6, a bomb exploded in the Moscow metro between the Paveletskaya and the Avtozavodskaya metro stations. Thirty-nine people died in the blast and more than 100 were injured. Presently, there are 98 injured in the hospital.