Secretary of State Hillary Clinton called on Russia Wednesday to stop arming Syrian President Bashar Assad's military, suggesting Russia was acting against its own interests by continuing to back the embattled regime. She warned the situation in Syria is "spiraling towards civil war."  

The secretary and other U.S. officials also unequivocally rejected Russia's accusation earlier in the day that the U.S. is arming the Syrian opposition. 

"The United States has provided no military support to the Syrian opposition. None," Clinton said. 

But a day after claiming Russia was providing attack helicopters to the Syrian government, Clinton said the U.S. has "repeatedly urged the Russian government to cut these military ties completely and to suspend all further support and deliveries."

The rapid-fire diplomatic battle between the two countries is quickly escalating as the U.S. tries to pressure Russia to pull back on its support for Assad amid worsening violence inside Syria. Both U.N. and French officials are now describing that conflict as civil war.