An ally and former adviser to Russian President Vladimir Putin and former President Boris Yeltsin said the country could use nuclear weapons against Europe should Russia ever be on the verge of

WASHINGTON, Jan 14 (Reuters) - U.S. President Donald Trump told Reuters that Ukraine - not Russia - is holding up a potential peace deal, rhetoric that stands in marked contrast to ​that of European allies, who have consistently argued Moscow has little interest in ending its war in ‌Ukraine.