LONDON (Reuters) - Oil prices jumped by about 1% on Monday, pushing Brent above $70 a barrel, as rhetoric from the United States, Iran and Iraq fanned tensions in the Middle East after a U.S. air strike killed a top Iranian military commander. Brent crude futures soared to a high of $70.74 a barrel and was at $69.36 by 1502 GMT, up 76 cents from Friday's settlement.U.S. West Texas Intermediate crude was up 54 cents at $63.59 a barrel after touching $64.72, its highest since April. The..