The ban, which was announced Wednesday, adds to a flurry of sanctions imposed by the outgoing Trump administration against Chinese officials, companies and goods over human rights, security and other complaints.
"The so-called forced labor issue is a "lie of the century" fabricated out of thin air", said Zhao Lijian, a spokesman for China's Ministry of Foreign Affairs.
China had an "appalling year" for human rights in 2020, a leading advocacy group said on Wednesday, with a crackdown on dissent in Hong Kong, repression of Muslim Uighurs and the silencing of people reporting on the coronavirus outbreak.
China says it aims only to promote economic and social development in the region and stamp out religious extremism, separatism and terrorism.
U.S. Customs and Border Protection said the order applies to raw fibers, apparel and textiles made from Xinjiang-grown cotton, as well as canned tomatoes, sauces, seeds and other tomato products from the region, even if processed or manufactured in third countries.
"We urge the USA side to respect facts, immediately withdraw its wrong decision and stop interfering in China's internal affairs under the pretext of Xinjiang-related issues", Zhao said.
The move follows a ban on cotton products from China's largest producer, the Xinjiang Production and Construction Corps. That makes the USA ban a potential challenge for retailers or clothing brands that will be required to ensure that their products are free of Xinjiang cotton.
"CBP will not tolerate the Chinese government's exploitation of modern slavery to import goods into the United States below fair market value", the agency's Acting Commissioner Mark A. Morgan said in a statement.
The British government will fine companies which hide connections to China's Xinjiang region where Uyghurs and other minorities are allegedly subject to forced labor, under a raft of new measures.
CBP officials said some 43 shipments of cotton-based products have been detained at USA entry ports since the XPCC ban was announced.
Estimates say the US ban affects about 20% of the global cotton supply.
British ministers are also looking to impose tougher export controls on goods and technology to China.
