While prices had reached unsustainable levels, the pace of gains the past two months was unexpected and shows markets are likely to remain volatile, Wickham said.

• 维克汉姆说，目前价格已经触及无法持续的高水平，过去两个月以来的攀涨势头出乎预料，显示市场可能仍旧处于动荡之中。