Russian airstrikes and military involvement in Syria are helping the Islamic State group, the Obama administration’s point man for defeating the terror group told Congress on Wednesday. What Russia calls counterterrorism is actually helping ISIS by pushing back against rebels who the U.S. says are fighting the group, he said.

Brett McGurk, a State Department official, told the House Foreign Affairs Committee that “what Russia’s doing is directly enabling ISIL,” using an alternate name for ISIS that is favored by President Barack Obama and his administration. McGurk plans on meeting with Russian diplomats and others from around the world at a conference on Syria this week and said that Russia’s actions are worsening the humanitarian crisis in Syria, fueling extremism and strengthening the Syrian government headed by Bashar Assad, according to the Associated Press.

That Russian President Vladimir Putin’s country is looking to prop up the Assad regime is not a secret and the two administrations have been able to look past horrific incidents, including the downing of a Russian airliner by a bomb over Egypt’s Sinai Peninsula in October, that pointed to the outright instability in the region.

In fact, Russia’s relatively recent involvement in the Syrian conflict has been called a “game changer” for Assad as it has enabled his forces to almost surround thousands of rebel fighters in Aleppo this month. In doing so, the Syrian regime may finally have the upper hand in its fight against the insurgent rebel forces that destabilized Assad’s regime.

That development is the result of a Russian-backed offensive around the city that has resulted in more than 500 deaths, according to the Christian Science Monitor. The Syrian forces appear likely to cut off the supply line between Aleppo and the Turkish border, which could leave as many as 300,000 civilians and 30,000 rebel fighters bottled up inside the city without access to supplies.