Japan’s biggest wireless carriers are looking at halting sales of new Huawei Technologies Co. phones, adding to woes of the Chinese mobile equipment maker that has been accused by the U.S. of posing a security threat.

NTT Docomo Inc., Japan’s largest operator, said Wednesday it is considering halting reservations for new Huawei products, while its rival KDDI Corp. said it would indefinitely delay introduction of Huawei’s P30 handset. YMobile Inc., a wireless phone brand operated by SoftBank, announced a similar move.

The steps underscore the stakes for Huawei, which has overtaken Apple Inc. as the world’s second-largest maker of smartphones and was on track to surpass the largest, Samsung Electronics Co. The Trump administration has blacklisted Huawei—which it accuses of aiding China in espionage—and has taken steps to cut off the U.S.-made software and semiconductors it needs to make smartphones and networking gear.

Docomo, KDDI and Ymobile didn’t say whether they would halt service or sales of all Huawei products.