Republicans, who control the U.S. Congress, have been pressuring the Democratic Obama administration to call the militants' atrocities in Iraq and Syria acts of genocide.
U.S. Secretary of State John Kerry is expected to find that the Islamic State militant group has committed genocide against Christians, Yazidis and Shi'ites, sources familiar with matter said on Thursday.
The sources, who spoke on condition of anonymity, said an announcement was expected later on Thursday, but declined to provide further details.
U.S. lawmakers urged Kerry last year to make a determination on whether atrocities committed by the militant group against Christians and other religious groups amounted to genocide. The State Department earlier had predicted it would miss a deadline set for Thursday on this decision.
Republicans, who control the U.S. Congress, have been pressuring the Democratic Obama administration to call the militants' atrocities in Iraq and Syria acts of genocide. This week, one chamber, the U.S. House of Representatives, passed a resolution labeling the group's violence against religious and ethnic minorities as genocide, war crimes and crimes against humanity.
A U.S. administration has not made a genocide finding since 2004, it determined genocide had occurred in Darfur and that the government of Sudan was responsible.