China's Foreign Ministry said on Wednesday that the country has maintained "normal, open and transparent" ties with Iran in the fields of economics, trade and energy.

Foreign Ministry spokesman Hong Lei made the remark at a regular press briefing in response to a question regarding possible U.S. sanctions against Iran, as the sanctions may affect Chinese companies that have trade ties with the country.

He said China's economic exchanges with Iran do not go against United Nations Security Council resolutions and "should not be affected."

China opposes placing domestic law above international law and does not favor unilateral sanctions against other countries, Hong said.

Hong said China believes Iran's nuclear issue should be solved through dialogues rather than sanctions.

On Saturday, U.S. President Barack Obama signed a wide-ranging defense funding bill, calling for new sanctions against financial institutions that do business with Iran's state banking institutions.