TAMPA — President Barack Obama has used his final address on global terror to defend his approach to the fight, calling for coalition-building to continue battlefield successes while rejecting the use of torture.

Highlighting the lines drawn during his eight years as commander in chief, Obama did not mention Donald Trump by name, but he clearly addressed his successor, who has yet to spell out his own counterterrorism strategy.

"Rather than offer false promises that we can eliminate terrorism by dropping more bombs or deploying more and more troops or fencing ourselves off from the rest of the world, we have to take a long view of the terrorist threat," Obama said on Tuesday.

"And we have to pursue a smart strategy that can be sustained."

Obama claimed a clear break from the strategy under former president George W Bush, highlighting the withdrawal of most US troops from Iraq and Afghanistan, from 180,000 to about 15,000 today. That number also includes advisors in Syria.

"Instead of pushing all of the burden onto American ground troops, instead of trying to mount invasions wherever terrorists appear, we’ve built a network of partners," he said.

Obama also defended his approach to fighting the Islamic State group in Iraq and Syria, much of it centered around an intense air strike campaign directed from MacDill Air Force Base.

The installation, where the president gave his speech, houses the headquarters of US Special Operations Command and CENTCOM, the US military’s command for operations stretching from the Gulf to Central Asia.

The jihadist group that wants to establish a "caliphate" straddling the two countries has lost "more than half" its territory, Obama said.

"ISIL has lost control of major population centres. Its morale is plummeting. Its recruitment is drying up. Its commanders and external plotters are being taken out, and local populations are turning against it."

Obama, who authorised the strike to take out al-Qaeda leader Osama bin Laden, said that the group was now "a shadow of its former self."

‘Greatest strength’

Obama stressed that the fight against terror should not come at the expense of civil rights and American democratic traditions.

"We need the wisdom to see that upholding our values and adhering to the rule of law is not a weakness. In the long term, it is our greatest strength," he said to sustained applause.

Trump, who has pledged to upend his predecessor’s entire agenda including foreign and security policy, takes over in the White House in just over six weeks.

He has not yet announced a nominee to head the State Department and has been vague at best about how he plans to defeat IS, but on the campaign trail he insisted that America must be "unpredictable" in order to win.

Obama touched on issues like torture that had provoked controversy during Trump’s White House run. The 44th president had banned extreme CIA interrogation techniques used on terror detainees as soon as he took office.

"We prohibited torture everywhere at all times and that includes tactics like waterboarding," he said.

"And at no time has anybody who has worked with me told me that doing so has cost us good intelligence."

On the campaign trail, Trump pledged to restore waterboarding -- a form of simulated drowning widely regarded as torture -- and permit "far, far worse."

But since his election, he seems to be softening his views -- a change that may reflect the influence of his nominee to head the Pentagon, retired marine general James Mattis.

Still, the threat of global terror will remain an issue "for years to come," Obama said.

He cautioned that extremists do not represent American Muslims, and that the US should never impose a religious test on its people, a reference to another controversial Trump campaign proposal.

"We’re a nation that believes freedom can never be taken for granted. And that each of us has a responsibility to sustain it, the universal right to speak your minds and to protest against authority, to live in a society that’s open and free, that can criticise our president without retribution."— AFP