The Biden administration has imposed sanctions on Syrian rebels for their involvement in the Turkish occupation of northern Syria on Wednesday.

The U.S. Treasury’s Office of Foreign Asset Control announced that Ahrar al-Sharqiya would be added to the “specially designated nationals” list, imposing economic sanctions on the Syrian militia.

The United States has rarely sanctioned Syrian insurgents, and has never sanctioned Turkey’s Syrian proxy army. Many of the other groups in the Turkish-backed Syrian National Army have received U.S. weapons and training. Ahrar al-Sharqiya fought alongside these groups but never received U.S. assistance.

“Ahrar al-Sharqiya has committed numerous crimes against civilians, particularly Syrian Kurds, including unlawful killings, abductions, torture, and seizures of private property,” the U.S. Treasury noted in a statement. “The group has also incorporated former Islamic State of Iraq and Syria (ISIS) members into its ranks. These horrific acts compound the suffering of a population that has repeatedly endured mass displacement.”

One of Ahrar al-Sharqiya’s most infamous crimes was the execution-style murder and mutilation of Syrian Kurdish politician Hevrin Khalaf in October 2019. At the time, then-U.S. special envoy James Jeffrey reportedly blocked a statement condemning the murder.

“It is good to sanction the groups that committed crimes,” Syrian Kurdish diplomat Sinam Mohamad wrote in a text message to Responsible Statecraft.

Turkey has launched several incursions against the U.S.-backed, Kurdish-led Syrian Democratic Forces, which Ankara says are linked to Kurdish rebels inside Turkey. The Trump administration gave a tacit green light to the 2018 operation, and an explicit one to the October 2019 campaign.

The Turkish military has used Syrian fighters to maintain control over occupied areas. Those fighters have been accused of war crimes, from looting property to holding civilians hostage in torture prisons.

The militias have also profited from the occupation, stealing from and extorting Afrini farmers whose olives were sold to American supermarkets.

Many of the rebel groups involved in the occupation used to receive weapons and training from the United States before joining the Turkish proxy force. Ahrar al-Sharqiya, which never received U.S. support, once threatened U.S. special forces deployed alongside Turkish-backed rebels in an infamous 2016 incident.

Earlier this month, the U.S. State Department added Turkey to the list of countries that use child soldiers, the first time a NATO ally was added to the list. The State Department accused the Sultan Murad Division — a formerly U.S.-backed, now Turkish-backed rebel group — of recruiting children to fight as mercenaries in Libya.

U.S. law allows Treasury to sanction entities that “threaten the peace, security, stability, or territorial integrity of Syria,” under an October 2019 executive order signed by then President Donald Trump in response to the Turkish invasion.

The order was used to sanction some Turkish officials, but those sanctions were lifted a week later. The executive order was also used to sanction the Syrian regime, which has committed atrocities against Syrian civilians but was not involved in the Turkish invasions.

However, the order was never used against the Turkish-backed militia groups. Mohamed, the Kurdish diplomat, had called for the U.S. government to designate those groups in an interview with Al-Monitor last week.

She told Responsible Statecraft on Wednesday that the United States should continue to sanction “many others” responsible for war crimes. Mohamed hails from Afrin, and her family olive business was looted during the Turkish occupation.

She said that she is “looking forward” to accountability for those “who robbed my property in Afrin.”