FXStreet (Edinburgh) - The Aussie dollar remains on the defensive today vs. the greenback, with AUD/USD challenging the key support at 0.6900. AUD/USD weaker as risk sentiment fades The risk-off trade is picking up pace early in Europe bolstered by another significant drop in the Chinese equities, exacerbating at the same time the offered tone around AUD. Spot has now erased earlier gains and is closing the week in red figures, trading in 4-month lows and opening the door for a test of 2015 lows in sub-0.6900 levels. AUD/USD key levels At the moment the pair is retreating 1.03% at 0.6912 with the next support at 0.6893 (2015 lows Sep.8) followed by 0.6283 (monthly low Feb.2009) and finally 0.6245 (monthly low Jan.2009). On the other hand, a surpass of 0.7050 (high Jan.12) would aim for 0.7141 (20-day sma) and then 0.7172 (55-day sma). For more information, read our latest forex news.