(CNN) -- Four police officers were killed Sunday by a suicide explosion in the center of Grozny, the capital of Chechnya, the Russian state-run RIA Novosti news agency reported, citing police at the scene of the attack.
A person approached the group in front of a concert hall and detonated, wounding nine people, the agency reported.
One civilian died in a hospital after the blast, another official news agency, Itar-Tass, reported.
Another four civilians remained hospitalized, one in serious condition, Itar-Tass added.