US President George Bush admitted that he signed a secret order after the September 11 terror attacks permitting surveillance of US citizens without court approval. In a live radio address Bush said it was a vital measure to protect US national interests. Earlier his administration's "war on terror" suffered a major setback after the US Senate blocked the renewal of the 'Patriot Act' - wide-ranging anti-terrorist legislation - by a vote of 52-47 with several opposition Democrats joining Republican senators to press their demands for safeguarding civil liberties.