President Barack Obama on Monday reminded Americans that his likely Republican opponent in the November election had been lukewarm about targeting Osama bin Laden, seeking to gain political advantage from the killing of the al-Qaida leader.

Obama accused Romney, the presumptive Republican presidential nominee, of being inconsistent on whether he would have ordered bin Laden's killing had he been president.

"I said that we'd go after bin Laden if we had a clear shot at him and I did," Obama said during a White House press conference. "If there are others who've said one thing, now suggest they'd do something else, then I'd go ahead and let them explain," he said, without mentioning Romney by name.

Obama's re-election campaign issued a video last week that highlighted Romney, in reference to bin Laden, remarking several years ago that it was "not worth moving heaven and earth spending billions of dollars just trying to catch one person".

Speaking on the eve of the first anniversary of bin Laden's killing by US Navy SEALs in Pakistan, Obama said there had been no "excessive celebration" of the moment by the White House. Obama's remarks were the latest volley in a not-so discrete White House campaign to allude to the bin Laden anniversary, while mostly letting the result of the event speak for itself.

Republicans have complained that the White House and Democrats are politicizing a moment they say should have been an opportunity for national unity. Romney insisted on Monday that "of course" he would have authorized the action against the man behind the Sept 11, 2001 attacks on Washington and New York.

CARTER 'WOULD HAVE GIVEN ORDER'

"Even Jimmy Carter would have given that order," Romney said in Portsmouth, New Hampshire, recalling the former Democratic president who was derided by critics for weak leadership during the 1979-1980 Iran hostage crisis.

The May 2 pre-dawn raid on bin Laden's compound a few hours drive from Islamabad - it occurred on May 1 Washington time - sent Americans onto the streets in celebration.

Obama said Americans would "rightly remember what we as a country accomplished in bringing to justice somebody who killed over 3,000 of our citizens", which he said was a time to reflect and "give thanks" to US intelligence and the military.

Obama traveled with his wife, first lady Michelle Obama, to a US military base on Friday at which he thanked US troops and special operations forces for their achievements, in a clear allusion to bin Laden's death.

Reuters