<span style="color: #222222;">The United States yesterday unveiled rules formally banning technology giant Huawei and other Chinese firms from government contracts. <br />'' <br />'' The move is a part of the escalating trade war between the two countries. The interim rule will preclude any US federal agency from purchasing telecom or technology equipment from the firms as a substantial or essential component, or as critical technology as part of any system.  <br />'' <br />'' The new rules are part of a sweeping effort by President Donald Trump's administration to restrict Huawei, which officials claim is linked to Chinese intelligence.</span><br />'' <br />''