sentences:  In August 1999, the War of Dagestan began when Chechen Islamists invaded the Russian state of Dagestan, but were defeated by the Russian military in a month.The War of Dagestan was used as a "casus belli" to trigger the Second Chechen War, when Russian federal troops entered Chechnya and ended its independence.By June 2000, the war had entered an "insurgency phase", where Russian troops would perform several day-long "zachistka" () operations that became notorious for their human rights violations.