SHANGHAI — Huawei, the embattled Chinese technology giant, is slashing its sales expectations for this year by around $25 billion as the Trump administration’s clampdown on the firm takes a bite out of its business.

At an event on Monday at Huawei’s headquarters in Shenzhen, the company’s chief executive, Ren Zhengfei, said he expected annual revenue to come in at about $100 billion both this year and next before recovering in 2021.

Last year, Huawei took in more than $105 billion in sales, helped by its fast-growing smartphone business. Mr. Ren said in January that he predicted another bumper year in 2019, with sales jumping to $125 billion.

But that was before the United States last month cut Huawei off from the American chips, software and other parts that go into its handsets and telecommunication equipment, saying that the company represented a threat to national security. American officials have long said Beijing could use Huawei’s products to disrupt or sabotage digital communications, accusations that the company vehemently rejects.