The dollar headed towards a weekly loss on Friday while bonds remained under pressure, after global central bankers warned that the Middle East war could reignite inflation. A dip in oil prices offered brief relief for markets, but trading stayed choppy and nerves frayed, highlighting how brittle investor confidence remains. Following a hectic week of monetary policy meetings across effectively the Group of Seven (G7) nations and others, the key takeaway for investors has been the prospect of a more aggressive policy tightening path.