"China's trade with Iran is normal business exchange, which will not harm the interests of other countries and the international community," said Jiang Yu, Foreign Ministry spokeswoman.
"As a permanent member of the UN Security Council, China has always observed the council's resolutions," she added.
On Monday, Aug 2, Robert Einhorn, the US State Department's special adviser for non-proliferation and arms control, asked China to fully back sanctions on both Iran and North Korea.
In Jun 2010, the UN Security Council imposed a fourth set of sanctions on Iran over its disputed nuclear drive, which the West and Israel say is a covert weapons drive, and especially over its refusal to freeze uranium enrichment.
China planned to invest 40 billion dollars in Iran's oil and gas industry.