The U.S. Congressional-Executive Commission on China, in an annual report published Wednesday, said Beijing's human rights record was an area of concern.
Committee Chairman U.S. Rep. Chris Smith, R-N.J., and Co-chairman Rep. Sherrod Brown, D-Ohio, said there was "visible frustration" and "well-founded impatience" with Beijing's lack of respect for basic human rights.
Brown pointed to a host of labor concerns ranging from low wages to unsafe work environments. Abuses against minority ethnic communities, meanwhile, were unprecedented.
The report calls on U.S. lawmakers and U.S. President Barack Obama to press Beijing to ratify existing civil and political treaties.
Chinese Foreign Ministry spokesman Hong Lei, in a statement published by the official Xinhua news agency, called on the committee to stop making "groundless remarks" against China.
He said the committee should favor facts over prejudices, warning the report may harm bilateral ties with Beijing.
Acrimony between Beijing and Washington has extended to the energy sector, where Beijing is accused of manipulating solar manufacturing markets. The U.S. Defense Department, meanwhile, has focused its efforts on the Asia-Pacific region, but has said it doesn't view Beijing as a regional aggressor.