(AGI) Washington, June 23 - Russia will face further sanctionsif it fails to stop the flow of arms and militants across theborder, said U.S. Vice President Joe Biden. He also called onMoscow to use its influence to persuade the separatists to laydown their arms, the White House reported. Ukraine PresidentPetro Poroshenko told Mr Biden on Sunday that, "Russian-backedseparatists continued to attack Ukrainian forces, includingusing artillery, following the ceasefire declaration[proclaimed by Kiev on Friday]". . .