For some time now, the US government and intelligence agencies have been warning consumers to not buy any Huawei smartphones. Major US wireless carriers came under pressure as well to back away from dealing with the company. Though, it appears that troubles for Huawei don't end there.
According to The Wall Street Journal, the US Department of Justice is looking into whether Huawei violated the country's sanctions against Iran. At this time, scope of the new probe is unclear, and we don't know of the specific allegations against Huawei. Though this does tell us that the US government is interested in how the company behaves at an international level.
Issues and warnings against Huawei have come from presumptions that the company has ties to the Chinese government. It's worth mentioning that the company's founder was a senior engineer with the Chinese Liberation Army.
The pressing issue here are concerns that if companies are allowed to work with Huawei, it might pave way for foreign government access to the US telecommunications network, which is a bad idea. To take it up a notch, Congress has proposed blocking Huawei from any government contracts and have advised ISPs, carriers and private citizens from buying any products from the company.