WASHINGTON -- US President Barack Obama announced his intention to strike the Islamic State "wherever they are" in an historic address to the American people on Wednesday night, preparing the nation for broad, borderless military conflict in the Middle East."We will conduct a systematic campaign of airstrikes against these terrorists," Obama said from the White House. "I will not hesitate to take action against ISIL [Islamic State] in Syria, as well as Iraq. This is a core principle of my presidency: if you threaten America, you will find no safe haven."Tweets by @mawilnerIn a fifteen-minute address, the president said the US would fight the group – which has conquered territories in eastern Syria and northern Iraq, and has threatened the United States – "relentlessly."White House officials say the president will now consider all territories in which the organization operates fair game for the US military, including Syria and the entirety of Iraq."It will take time to eradicate a cancer like ISIL," he said. "And any time we take military action, there are risks involved."But "our own safety – our own security – depends upon our willingness to do what it takes to defend this nation, and uphold the values that we stand for," he continued, "timeless ideals that will endure long after those who offer only hate and destruction have been vanquished from the Earth."The president also noted the addition of 475 new military personnel on the ground in Iraq, while vowing to the American people that the slow addition of manpower did not amount to a resumption of war in the country, for a third time in 24 years.Senior administration officials prepared White House journalists for strikes against Islamic State targets in Syria at a "time and place" of the president's choosing, but said that the decision had already been made."In Iraq, we are going to expand the efforts of our air campaign," one official said. "If there is an ISIL target that we need to hit in Iraq, we will hit it."And in Syria, air strikes are "something that the president has decided to do," the official continued. "We will take action."The president will also seek funding from Congress for Syrian rebels vetted and approved by the US, which can serve as a ground force to hold ground cleared by the US Air Force.Obama says he believes he has the authority to act without Congress providing him with authorization for the use of force, based on a 2001 authorization vote, allowing the president to target al-Qaida and its affiliates.Islamic State, also known as ISIS and ISIL, was originally known as al-Qaida in Iraq, or AQI, during the Iraq War."We have ramped up our military assistance to the Syrian opposition," Obama said Wednesday. "Tonight, I again call on Congress to give us additional authorities and resources to train and equip these fighters."Foreign nations will join the US in its air campaign, US officials said, although "conversations are now under way" on what nations will play what roles in the coalition. Instead of military power, some may instead provide funding and training for rebels, while others still will contribute political support. "He does not shoot first and ask questions later," one other official said of the president. "We are poised to go on offense."The Pentagon is prepared to begin strikes as ordered, one senior defense official said after the speech."The US military is ready to conduct direct action against ISIL targets in Syria," the defense official said. "Decisions about when to conduct these actions will be made at a prudent time."US Defense Secretary Chuck Hagel, too, said the army was prepared to launch the broad offensive upon the president's order."The men and women of the US armed forces are ready to carry out the orders of our commander-in-chief, to work with our partners across government, and to work with our friends and allies around the world to accomplish this mission," Hagel said.From Jordan, US Secretary of State John Kerry said that the US effort to build an international coalition against Islamic State is already well under way. Kerry was in Baghdad on Wednesday, lauding the creation of a new, inclusive government that could take on the security challenge of the group."We are uniting the world against a unified threat, and the president's strategy will succeed because doing it with allies and partners isn't just smart, it's strong," Kerry said.The secretary will also travel to Saudi Arabia this week to rally support for the fight. US officials say the Saudis are prepared to "fully cooperate" with the US on training moderate Syrian rebels to help combat the group."Defeating this common enemy calls for a common cause, and we're taking it on to succeed together," Kerry continued.