Huawei Technologies Co. is planning extensive layoffs at its U.S. operations, according to people familiar with the matter, as the Chinese technology giant continues to struggle with its American blacklisting.

The layoffs are expected to affect workers at Huawei’s U.S.-based research and development subsidiary, Futurewei Technologies, according to these people. The unit employs about 850 people in research labs across the U.S., including in Texas, California and Washington state.

Huawei...