By Sybille de La HamaidePARIS, April 3 (Reuters) - World food prices climbed in March to their highest level since September last year and could rise further if the Middle East conflict that pushed up energy prices continues, the United Nations Food and Agriculture Organization said on Friday."Price rises since the conflict began have been modest, driven mainly by higher oil prices and cushioned by ample global cereal supplies," FAO Chief Economist Maximo Torero said in a statement.