"The Chinese side expresses strong indignation over the above-mentioned unreasonable practices of the US side," foreign ministry spokesman Geng Shuang told a regular press briefing.

Geng said Beijing had lodged an official protest with the United States.

"The US actions have seriously violated the basic principles of international relations and seriously damaged the relations between the two countries and the two militaries," Geng said.

"We strongly urge the US to immediately correct their mistake and withdraw their so-called sanctions, otherwise the US will have to bear the consequences."

The US State Department said Thursday it was placing financial sanctions on the Equipment Development Department of the Chinese Ministry of Defence, and its top administrator, for the recent purchase of Russian Sukhoi Su-35 fighter jets and S-400 surface-to-air missiles.

Officials said it was the first time a third country has been punished under the CAATSA sanctions legislation for dealing with Russia, and signalled the Trump administration's will to risk relations with other countries in its campaign against Moscow.

The move comes as the United States and China are in the heat of a trade war.

The two countries will launch new tariffs on Monday, with Washington targeting $200 billion in Chinese exports and Beijing hitting $60 billion worth of American products.

The two sides have already imposed tariffs on $50 billion in goods from each country.