"As president, I would pursue a new strategy, and begin by providing at least two additional combat brigades to support our effort in Afghanistan. We need more troops, more helicopters, better intelligence-gathering and more nonmilitary assistance to accomplish the mission there," he wrote in a stinging opinion piece in the New York Times.

"I would not hold our military, our resources and our foreign policy hostage to a misguided desire to maintain permanent bases in Iraq," the 47-year-old Senator from Illonis wrote while describing military interventions in Iraq and Afghanistan as "the greatest strategic blunder in the recent history of American foreign policy."

Obama, who aspires to be the first black-American president said that ending the war in Iraq was essential to meet America's "broader strategic goals, starting in Afghanistan and Pakistan, where the Taliban is resurgent and Al Qaeda has a safe haven."

"Iraq is not the central front in the war on terrorism, and it never has been," he said while quoting Admiral Mike Mullen, the chairman of the Joint Chiefs of Staff, to say that the US will not have "sufficient resources to finish the job in Afghanistan until we reduce our commitment to Iraq."