Russian authorities say one person has been killed and three others detained in an operation to break up a sleeper cell of ISIS in the country's restive southern region of Dagestan.
The National Anti-terrorism Committee said the operation took place Sunday in the city of Derbent, on the Caspian Sea near the border with Azerbaijan.
The committee said in a statement that one militant was killed by police after they blockaded his house and he opened fire. Three others were arrested at other locations.