China expressed opposition on Friday to the sanctions imposed by the United States on its enterprises for alleged support of Russia in the Ukraine crisis, urging Washington to immediately stop tarnishing and oppressing Beijing.

The US on Thursday sanctioned two Chinese companies and a Russian affiliate involved in making and shipping "attack drones", the first US sanctions imposed on Chinese entities which Washington alleges are "directly developing and producing complete weapons systems in partnership with a Russian firm".

The two targeted Chinese companies are Xiamen Limbach Aircraft Engine Co Ltd and Redlepus Vector Industry Shenzhen Co Ltd, which the US Treasury Department accused of being involved in the development and production of Russia's Garpiya series of long-range unmanned aerial attack vehicles.

China firmly opposes the illegal and unilateral sanctions, and will never accept unwarranted accusations and oppression from the US, Foreign Ministry spokeswoman Mao Ning said at a daily news briefing.

China has never provided any deadly weapons to either side in the Ukraine crisis, and exercises strict export controls over dual-use items including drones, Mao said, adding that the country opposes using civilian drones for military purposes.

She urged the US to stop imposing sanctions and long-arm jurisdiction on Chinese firms and individuals, vowing to take all necessary measures to safeguard the legitimate rights and interests of Chinese citizens and companies.

Washington has repeatedly accused Beijing of supporting Russia in its conflict with Ukraine, which has become one of the negative factors in their efforts to stabilize ties.

China did not start and is not involved in the crisis, the spokeswoman said, reiterating that the country always plays a constructive role in pushing for a political settlement of the Ukraine crisis through peace talks.