American lawmakers have voted to label Islamic State group atrocities in Syria and Iraq "genocide," and called for setting up Syrian war crimes tribunal under United Nations authority.
The House of Representatives unanimously passed a non-binding resolution pressuring President Barack Obama's administration to call attacks against Christians, Yezidis and other minorities "war crimes, crimes against humanity and genocide."
The State Department has so far declined to use that label.
In a second measure, representatives voted 392 to 3 for a resolution urging the White House to urge the UN Security Council to immediately establish a Syrian war crimes tribunal, calling actions by the Syria's government and others "gross violations of international law amounting to war crimes and crimes against humanity."
"What is happening in Iraq and Syria is a deliberate, systematic targeting of religious and ethnic minorities," said House Speaker Paul Ryan, a Wisconsin Republican.
"Today, the House unanimously voted to call ISIS's atrocities what they are: a genocide."
Congress has set a March 17 deadline for the State Department to formally decide whether to issue a comprehensive genocide designation, although it is expected to miss that date.
State Department spokesman John Kirby said that Secretary of State John Kerry would reach a determination "soon."
Foreign Affairs Committee Chairman Ed Royce, a Republican from California, urged the White House not to "drag out" a decision.
"ISIS is guilty of genocide," he said.
"It has been using mass murder, beheadings, crucifixions, rape, torture and enslavement in its deliberate campaign to eliminate religious minorities and bulldoze their history."
He pressed the Obama administration to "seek accountability for Bashar al-Assad's heinous war crimes against his own people," noting that more than 18,500 children are among the hundreds of thousands of people killed in the brutal conflict.
During the debate, representatives called for establishing an ad-hoc or regional tribunal as opposed to one at the International Criminal Court (ICC).
Past courts, including for Sierra Leone, Rwanda and the former Yugoslavia "have made a significant difference holding some of the worst mass murders to account with successful prosecutions followed by long jail sentences," Republican Representative Chris Smith said.
"The ICC has operated since 2002 but boasts only two convictions."
The UN is set to host a new round of peace talks over Syria's conflict in Geneva on Tuesday, which marks the fifth anniversary of Syria's war.
It will be the latest effort to end violence that has killed more than 270,000 people and displaced millions.