Russia warns U.S. against arms to Ukraine as Biden due in Kiev

U.S. Vice President Joe Biden (L) and his wife Jill wave upon their arrival at Boryspil International airport outside Kiev November 20, 2014. REUTERS/Valentyn Ogirenko

MOSCOW/KIEV (Reuters) - Russia warned the United States on Thursday against supplying arms to Ukrainian forces fighting pro-Russian separatists in eastern Ukraine, hours before U.S. Vice-President Joe Biden was due to arrive in Kiev.

Ukraine accused President Vladimir Putin of treating its territory like a "playing field", trying to unleash a full-scale war that would pose a broader threat to NATO countries.