China firmly opposes the United States' illegal unilateral sanctions that have no basis in international law and have not been authorized by the United Nations Security Council, Foreign Ministry spokesman Lin Jian said on Friday.

Lin made the remarks at a regular news conference in response to a question about the US Treasury Department's announcement earlier this week of sanctions on nine individuals and entities from the Chinese mainland and Hong Kong, on the grounds that they allegedly helped Iran purchase military supplies.

"We have said many times that China firmly opposes illegal unilateral sanctions that have no basis in international law and have not been authorized by the UN Security Council," Lin said.

China will take all necessary measures to firmly safeguard the legitimate rights and interests of its companies and citizens, he said.