<span style="color: #222222;">US President Donald Trump stepped up his criticism of internet firms today, hours after attacking Google over what he called "bias" against him and his supporters.</span><br />'' <span style="color: #222222;">  </span><br />'' <span style="color: #222222;">Talking to media in White house ,Mr.Trump said "Google , Twitter and Facebook  are really treading on very troubled territory and they should be  careful.</span><br />'' <br />'' <span style="color: #222222;">The comments come after the president last week slammed social media firms for what he claimed was suppression of conservative voices.</span><br />