According to the ministry, one of the militants is believed to have been involved in a bomb attack on a police car in the Urus-Martan district in the troubled North Caucasus republic on April 26, 2004, which killed one policeman and wounded two others.
The second militant is charged with setting off a remote-controlled bomb on June 4, 2005, which killed one interior troops soldier and injured two others, the ministry said.
The other two gunmen are accused of preparing an attack on police in the capital of Grozny on April 11, 2002 by planting a roadside bomb. The bomb attack failed because no one was hurt in an explosion.
According to the ministry, all the four detained persons are active members of armed gangs in the republic. Police have launched investigations into the militants' possible involvement in other attacks on federal troops.
