The White House on Monday said the anticipated expansion of its military efforts in Iraq and possibly Syria amounted to a counter-terrorism operation akin to the killing of Osama bin Laden and the fight against “core al-Qaida” in Afghanistan and Pakistan.

The comparisons drew a tacit contrast with the last major US military offensive in the region – the 2003 invasion of Iraq.

Obama will address the nation on Wednesday – the eve of the September 11 anniversary – to give details of how he plans to execute his “degrade and destroy” strategy against Isis. The White House was on Monday finalising its plan for a sustained confrontation against the group, which could involve extending air strikes in Iraq to the jihadist group’s strongholds in Syria.



“The president is concerned about the threat of terrorism, and that is why the other counter-terrorism operations that this administration has carried out are a relevant reference point,” said White House spokesman Josh Earnest at a daily briefing. “What the president’s trying to do is to try and illustrate that there’s a track record here.”



The president’s top concern, the White House said, was the threat against US personnel inside Iraq – and “the threat that this extremist organisation principally poses to the homeland.”

There are “individuals with western passports that have traveled to the region and taken up arms to fight alongside Isil,” Earnest said, using the administration’s preferred acronym for Isis. “There is significant concern about the idea that some of these individuals may try to travel back to the west using their western passports and carry out acts of violence or engage in terrorism here.”

Asked whether the new military effort would extend to air strikes inside Syria, Earnest said the president would go “wherever is necessary,” and offered the 2011 killing of Osama bin Laden as instructive.

“What the president has said is his willingness to go wherever is necessary to strike those who are threatening Americans,” Earnest said. “And that has been true in a range of other circumstances, to the extent that there are parallels here. The president ordered this military mission to go after Osama bin Laden in Pakistan … I think that is a useful guideline as you try to assess the president’s thinking about some of these issues.”



In advance of Obama’s speech, Obama will meet congressional leaders in Washington, where Democrats and Republicans are receptive to intensifying the fight against Isis. Hawks from both parties are urging the White House to attack Isis in regions of Syria where it has solidified its power base.



However, officials in the administration were still believed to be undecided about the wisdom of switching the focus from Iraq to Syria. The decision is expected to rest in part on the response from the international community to Wednesday’s speech.

The State Department has dispatched diplomats across the Middle East, convinced that an expanded confrontation against Sunni extremists can only succeed with the backing of key regional powers including Saudi Arabia, Qatar and the United Arab Emirates.

The Arab League on Monday agreed in a resolution to combat Isis extremists, but the statement from the 22-member body was vague, and stopped short of explicitly backing US military action.

Obama, whose six years in office have been characterised by a reluctance to become embroiled in military conflicts abroad, is wary of comparisons to the Iraq war, and he has repeatedly stressed that any confrontation against Isis will not involve combat troops on the ground in the Middle East.

But administration officials privately acknowledge that the US may be involved in an intensified and prolonged military engagement in the region, albeit one restricted to assaults from the air and support for Kurdish, Iraqi and other local military factions.

There are signs that US attacks against Isis fighters in Iraq are set to expand, amid intense debate in the White House and the Pentagon, over whether the campaign should include bombing across the border in Syria. Obama ordered the US military to conduct more than 130 air strikes against Isis over the past month. There are more than 1,000 US ground troops in Iraq now, under a legal basis that has recently been called into question.

On Sunday, US warplanes launched attacks in Anbar province – the first time jets have bombed the western region since it fell into Islamist control earlier this year. The Pentagon said the five strikes destroyed four Humvees and four armed vehicles belonging to the jihadists, including two carrying anti-aircraft artillery.

Following last week’s Nato summit in Wales, the White House believes it has enough support from key partners to build an international coalition for action against Isis, even though officials acknowledge they face greater resistance from the countries in the Middle East.

“This is a galvanizing moment for Nato and our partners,” the defence secretary Chuck Hagel said on a visit to Georgia over the weekend.

Obama’s speech on Wednesday will be pivotal. His administration has struggled to recover from the president’s recent admission that “we don’t have a strategy yet” for confronting Isis, which has taken over large parts of Iraq and Syria in a conflict that has become a magnet for extremist fighters.

Since then, Obama has adopted an unusually aggressive position against Isis, which his top intelligence advisers believe could overtake al-Qaida as the world’s most dangerous threat. Obama told NBC’s Meet The Press on Sunday that he was “preparing the country” for a confrontation with Isis.

“The next phase is now to start going on some offense,” he said. “But this is not going to be an announcement about US ground troops. This is not the equivalent of the Iraq war. This is similar to the kinds of counter-terrorism campaigns we’ve been engaging in consistently over the last five, six, seven years.”

The White House believes it has the power to continue strikes in Iraq and possibly expand air operations into Syria without congressional authorisation, but Obama is determined to secure an endorsement from lawmakers. “I do think it’s important for Congress to understand what the plan is, to buy in, to debate it,” he said.

The Obama administration also wants to seize on the current appetite for a forceful response to Isis to persuade Congress to grant his longstanding request for $500m to train and arm vetted groups in the Syrian opposition.