Huawei Technologies Co Ltd’s planned deal with US carrier AT&T Inc to sell its smartphones in the United States has collapsed at the eleventh hour, people with knowledge of the matter said, in a blow to the Chinese firm’s global ambitions, Reuters reported. A separate person familiar with the discussions said that security concerns had arisen, without elaborating further. AT&T was pressured to drop the deal after members of the US Senate and House intelligence committees sent a letter on Dec. 20 to the Federal Communications Commission citing concerns about Huawei’s plans to launch consumer products through a major US telecom carrier, online tech news site The Information reported. Huawei said in a statement to Reuters on Tuesday that its flagship premium smartphone Mate 10 Pro—Huawei’s challenger to the iPhone—will not be sold in the United States via a telecoms carrier but only through open channels.