Russia is playing the role of "both arsonist and firefighter" in Syria, Gen. Joseph Votel, who oversees all US troops in the Middle East, said Tuesday.
"Diplomatically and militarily, Moscow plays both arsonist and firefighter: fueling tensions among all parties in Syria, the Syrian regime, Iran, Turkey, the Syrian Democratic Forces, the United States and other coalition partners, then serving as arbiter to resolve the disputes, attempting to undermine and weaken each party's bargaining positions," Votel told a hearing of the House Armed Services Committee.
US officials have previously criticized both Russia's military efforts in Syria as well as several diplomatic efforts that American officials have seen as attempts to circumvent the UN-backed Geneva process, which seeks to bring about an end to the Syrian civil war.
The UN Security Council passed a resolution Monday demanding a 30-day cessation of hostilities throughout Syria, and Russia announced that it was working with the regime of Syrian leader Bashar al-Assad to establish a daily five-hour "humanitarian pause" for the Damascus suburb of Eastern Ghouta.
The pause seemed to have little impact Tuesday, as shelling and artillery fire continued.
US and UN officials have accused the Russian-backed Syrian regime of carrying out an indiscriminate aerial bombardment of the area.
Votel said continued regime aerial attacks in Eastern Ghouta appeared to show that Russia is incapable of or unwilling to hold the regime to account.
"As we look at the UN-sanctioned ceasefire that was put in this place, one that they helped draft and agreed to implement and to cause the regime to comply by it -- they have failed to do that," Votel said.
"I think either Russia has to admit that it's not capable or it doesn't want to play a role in ending the Syrian conflict here," Votel added, saying, "I think their role is incredibly destabilizing at this point."
Votel said Moscow was pursuing its own interests in Syria and was also undermining the fight against ISIS.
"Despite the key role that our partners on the ground, the Syrian Democratic Forces, and the coalition have played in dealing defeat to ISIS, Russia has placed this progress at risk with their activities, which are not focused on defeating ISIS but rather on preserving their own influence and control over the outcome of the situation," Votel said.
"It is clear that Russia's interests in Syria are Russia's interest and not those of the wider international community," he added.