President Obama announced an escalation of the war against Islamic State terrorists Wednesday night with plans to intensify airstrikes in Iraq, send more U.S. military advisers to Baghdad, provide arms to Syrian rebels and likely expand airstrikes into Syria.
“If left unchecked, these terrorists could pose a growing threat beyond that region — including to the United States,” Mr. Obama said in a prime-time address from the White House. “We will conduct a systematic campaign of airstrikes against these terrorists.”
The president ordered another 475 military advisers to Iraq, on top of 300 advisers he sent there in June and 130 U.S. personnel he sent last month to aid in a humanitarian mission.
In addition to ramping up the bombing missions that will be flown by U.S. warplanes and drones against the Islamic State in Iraq, Mr. Obama said the air war likely will be expanded into Syria when U.S. reconnaissance missions identify more targets of the terrorist organization also known by the acronyms ISIL and ISIS.
Indeed, in an echo of President George W. Bush’s anti-terror doctrine, he specified that terrorists will not be safe in any country.
“I have made it clear that we will hunt down terrorists who threaten our country, wherever they are,” Mr. Obama said. “That means I will not hesitate to take action against ISIL in Syria, as well as Iraq. This is a core principle of my presidency: If you threaten America, you will find no safe haven.”
While the president outlined a multipronged military and diplomatic strategy for going on the offensive against the surging Sunni militants, he took pains to contrast the expanded campaign with Mr. Bush’s wars in Afghanistan and Iraq.
For example, he referred to this campaign, which has surpassed more than 150 airstrikes in Iraq, as a counterterrorism operation instead of a war — a word he used in only two references to what his plan is not.
“I want the American people to understand how this effort will be different from the wars in Iraq and Afghanistan,” Mr. Obama said. “It will not involve American combat troops fighting on foreign soil. This counterterrorism campaign will be waged through a steady, relentless effort to take out ISIL wherever they exist using our air power and our support for partner forces on the ground.”
The strategy, unveiled just two weeks after Mr. Obama said he had no plan for defeating the militants in Syria, will rely on the U.S. and its allies arming moderate Syrian rebels who are battling both the Islamic State and the regime of President Bashar Assad in a 3-year-old civil war.
While some in Congress have been urging Mr. Obama for years to arm the Syrian rebels, other lawmakers reacted warily to the plan.
“We have to make sure that we’re not putting weapons into the hands of al Qaeda or other jihadis,” Rep. Peter T. King, New York Republican, said on CNN.
In Iraq, the president said the formation of a new government under Prime Minister Haidar al-Abadi will be the key to rehabilitating the dubious Iraqi army and taking the fight to the militants.
“With a new Iraqi government in place, and following consultations with allies abroad and Congress at home, I can announce that America will lead a broad coalition to roll back this terrorist threat,” Mr. Obama said. “Our objective is clear: We will degrade, and ultimately destroy, [the Islamic State] through a comprehensive and sustained counterterrorism strategy.”
On the eve of the 13th anniversary of the 9/11 terrorist attacks, Mr. Obama’s announcement of the military escalation was a dramatic turnaround by a president who dismissed the Islamic State nine months ago as a “JV” terrorist group. Last year, the president told Americans that the large-scale war against Islamist extremism was all but over.
The gains by the terrorist group have brought Mr. Obama to a decision to carry out a military campaign in Syria only one year after he announced — and then withdrew — plans to launch missile attacks against the Assad regime for using chemical weapons in the civil war.
Although Mr. Obama didn’t announce a specific air campaign in Syria, aides said U.S. airstrikes against militants there are only a matter of time.
“We are going to take airstrikes in Syria at a time and place of our choosing,” said a senior administration official. “We will take action on the Syrian side of the border … but we’re not going to telegraph our punches.”
Mr. Obama has said he has the authority to proceed with much of his plan without formal approval from Congress. But he is seeking lawmakers’ authorization for $500 million to train and equip Syrian rebels, a request he first made in May in a speech at the U.S. Military Academy at West Point.
House Republicans raised a potential roadblock for that operation Wednesday by not including the measure in temporary funding legislation. Mr. Obama and Vice President Joseph R. Biden were calling lawmakers and urging them to include the authorization in the funding bill.
The president also ordered $25 million under the Foreign Assistance Act to be spent on equipment and training for the Iraqi army, including Kurdish forces.
House Speaker John A. Boehner said after the speech that Mr. Obama made a welcome turn and “recanted his earlier dismissals of ISIL’s capabilities and rightly acknowledged the grave and growing threat posed by the spreading global epidemic of radicalized Islam.”
But the Ohio Republican said questions remain about the president’s plan because training Iraqi forces “could take years to fully implement at a time when ISIL’s momentum and territorial gains need to be immediately halted and reversed.”
“It is also a cause for concern that the president appears to view the effort against ISIL as an isolated counterterrorism campaign, rather than as what it must be: an all-out effort to destroy an enemy that has declared a holy war against America.”
Before the speech, Sen. Ted Cruz, Texas Republican, said Mr. Obama must seek congressional authorization for proposed military action against the Islamic State.
“Only Congress has the authority to declare war. While our commander in chief has constitutional authority to respond to an imminent danger, Obama has not suggested that is the case,” Mr. Cruz wrote in an op-ed for CNN. “He is reportedly planning a mission that could last as long as three years and may require a range of actions.”
Some Democrats, too, are expressing reservations about expanding the offensive. Rep. John Garamendi, California Democrat, said he wants to make sure the plan isn’t limited to airstrikes.
“We cannot win this with bombing,” he said. “This is going to have to be a diplomatic effort with the countries in the area coming together and deciding it is in their best interests to stifle and snuff out [the Islamic State].”
After Mr. Obama’s speech, several liberal advocacy groups reacted negatively to the president’s plan.
“We remain deeply troubled by any plan for U.S. military engagement that has not been explicitly debated by the American people and voted on by Congress,” said Neil Sroka, a spokesman for Democracy for America. “After more than a decade of war, the American people and their representatives in Congress must have a calm, rational public debate of that response and the appropriate level of U.S. involvement.”
The president and his top advisers also were working to firm up a coalition including Arab states to fight the militants. Mr. Obama spoke by phone with King Abdullah of Saudi Arabia, ahead of a gathering of Arab leaders on their contributions to a global coalition against the Islamic State.
Secretary of State John F. Kerry is heading to Saudi Arabia and Jordan this week, after stopping in Baghdad on Wednesday to meet with Iraq’s new leaders and pledging U.S. support for eliminating the extremist group and the threat it poses.
Mr. Kerry said the Iraqis have achieved a historic result by forming a new government under Prime Minister Haidar al-Abadi, a key to Mr. Obama’s plan to rebuild the Iraqi army to fight the militants more effectively.
“This is a broad-based, comprehensive strategy that is being laid out,” Mr. Kerry said. “And it will not just be reserved to bombs or direct military assistance. It will be comprehensive with Iraqi forces on the ground in Iraq with an army that will be reconstituted and trained and worked on in terms of a number of different strategies.”
France’s foreign minister said his country was ready to take part in airstrikes against extremist fighters in Iraq if needed. The German government announced that it was sending assault rifles, ammunition, antitank weapons and armored vehicles to Kurdish forces in Iraq, breaking with the NATO member’s decadeslong reluctance to send weapons into conflict areas.
Mr. Kerry also announced that the U.S. is providing nearly $48 million in additional humanitarian aid for Iraqis internally displaced and refugees who have fled to Jordan, Lebanon and Syria. It brings the total amount of U.S. humanitarian assistance to displaced Iraqis to more than $186 million in fiscal year 2014.
⦁ S.A. Miller contributed to this article, which is based in part on wire service reports.