US President Obama\'s advisor for Combat of Terrorism John Brennan said that all options remain open in order to help the Syrian opposition in their battle against Bashar al-Assad\'s regime including imposition of a no-fly zone in Syria. Brennan asserted that the US Administration has actually provided support in various ways to the opposition fighters including humanitarian aid. The United States of America is contemplating scenarios and emergency plans as the situation is develops in Syria, he revealed. The CNN quoted Brennan as saying before the US Foreign Relations Council in Washington last night that \"these are things into which the US Government is looking with utmost diligence. The President keeps us very busy in order to ensure that we are capable of doing everything in order to ensure peace reigns in Syria without risking an escalation of violence. Regarding whether the imposition of a no-fly zone was one of the current options, Brennan said that I do not remember at any point in time that the President has ruled out any option on the table. Since the beginning of this month, US officials said that Obama had signed a \"clandestine\" ordinance which permits provision of support to the Syrian opposition fighters. They said that the confidential order allows the US Central Intelligence Agency and other US bodies to provide assistance to the Syrian opposition fighters who seek to oust al-Assad\'s regime. However, it was not clear what the nature of such support could be, especially after Washington had ruled out arming the Syrian opposition and was sufficed with providing them with other assistance. The US Administration pledged to assist the Syrian opposition when the UN Security Council failed last month to reach any agreement in favor of imposition of stricter sanctions against al-Assad\'s regime which has unleashed an all-out military campaign against the opposition, killing and displacing tens of thousands of refugees according to international statistics.