Sudan has rejected US threats of sanctions saying such decisions were not \"neutral\" and aimed at punishing Sudan and rewarding the aggressor, in reference to neighbouring South Sudan. The chairman of Sudan\'s National Congress Party (NCP), Dr Qotbi al-Mahdi, said \"all the indications and practices of the government of South Sudan and its obstinacy in negotiations, its ties with Israel and other hostile countries reflect its rejection of peace and its aim to ignite war against Sudan\". Al-Mahdi also dismissed the opposition\'s announcement that it would overthrow the government.  Responding to queries by the media on opposition efforts to renew its alliances, he said that all the reasons given by the opposition, such as the economic crisis, corruption or other reasons, were \"not sufficient causes for toppling the regime\".  Meanwhile, he called on the opposition to prove its worth and produce alternative solutions for the current issues.  He said that the government\'s failure should be proved by producing alternative programmes and policies.