The most-traded iron ore, for delivery in January next year, on China's Dalian Commodity Exchange DCIOcv1 ended daytime trade 0.6% lower at 730.50 yuan ($108.42) a tonne. The contract, however, was on track for a weekly gain of more than 2% driven by a rebound in margins at mills.
On the Singapore Exchange, the front-month September contract SZZFU2 was down 1.8% at $110.25 a tonne, as of 07:00 GMT.
"The iron ore market remains on shaky ground," ANZ commodity strategists said in a note. "Demand in China still faces headwinds from a real estate downturn and constraints on steel industry emissions."