The U.S. sanctioned Syrian Defense Minister Ali Abdullah Ayoub, the Treasury Department's Office of Foreign Assets Control announced Thursday.
Ayoub has been added to the department's Specially Designated Nationals And Blocked Persons List, and any of his assets subject to U.S. jurisdiction have been frozen. Americans are now generally prohibited from conducting business with him.
The designation comes amid a halt to the Syrian regime's offensive on Idlib, in the country's northwest, that has displaced some 900,000 people according to UN estimates.
Idlib falls within a de-escalation zone laid out in a deal between Turkey and Russia in late 2018. The Syrian regime and its allies, however, have consistently broken the terms of the ceasefire, launching frequent attacks inside the zone.
Hundreds of thousands of people have been killed and over 10 million others displaced during the course of the Syrian conflict, now in its tenth year.
By Michael Hernandez in Washington