WASHINGTON (Reuters) - US President Barack Obamas new national security strategy will make clear the United States is not at war with Islam, a top adviser said on Wednesday as the administration prepared for a formal break with Bush-era doctrine. The White House on Thursday (today) plans to roll out Obamas first formal declaration of national security goals, which are expected to deviate sharply from the go-it-alone approach of his predecessor that included justification for pre-emptive war. Previewing parts of the document, John Brennan, Obamas leading counterterrorism adviser, said: We have never been and will never be at war with Islam. The Presidents strategy is unequivocal with regard to our posture - the United States of America is at war. We are at war against Al-Qaeda and its terrorist affiliates, he said in a speech at the Centre for Strategic and International Studies in Washington. Brennans words dovetailed with Obamas outreach to the Muslim World, where former president George W Bush alienated many with the US-led invasion of Iraq and his use of phrases like war on terror and Islamo-fascism. Brennan said curbing the growing threat of homegrown terrorism would be a top priority, along with boosting defences against lone Al-Qaeda recruits who hold foreign passports that allow them to enter the US with little to no screening. Brennan made clear there would be no let-up in the counterterrorism fight, saying the US would need a broad campaign that harnesses every tool of American power, military and civilian, kinetic and diplomatic. We will take the fight to Al-Qaeda and its extremist affiliates wherever they plot and train - in Afghanistan, Pakistan, Yemen, Somalia and beyond, he said. We will not simply degrade al Qaedas capabilities or simply prevent terrorist attacks against our country or citizens, we will not merely respond after the fact, after an attack that has been attempted, Brennan said. Instead the US will disrupt, dismantle and ensure a lasting defeat of Al-Qaeda and violent extremist affiliates, he said.