LONDON—The world’s biggest mobile carrier outside China said it is temporarily halting purchases of some components made by Huawei Technologies Co., posing a threat to the Chinese company’s growth and dealing another blow to its reputation amid increasing government scrutiny around the globe.

Vodafone Group PLC said Friday that it would pause the purchase of Huawei gear for use in the core of new 5G networks it is rolling out across Europe. It cited uncertainty in that market particularly over whether some governments in...