China's Huawei Technologies, which for years has denied violating American trade sanctions on Iran, was directly involved in sending prohibited U.S. computer equipment to Iran's largest mobile-phone operator, internal company records show.

Among more than 100 pages of documents related to Huawei projects, two packing lists dated December 2010 for goods destined for the Iranian carrier included equipment made by Hewlett-Packard Co.

Another Huawei document, dated two months later, stated, "Currently the equipment is delivered to Tehran, and waiting for the custom clearance."