Tillerson told Fox News that US President Donald Trump had been very clear that the policy he announced this week was a dramatic shift from a time-based military strategy to a conditions-based strategy, "which means it will be dictated by conditions on the ground informed by battlefield commanders."
"He has delegated significant authority to Defence Secretary (James) Mattis to set troop levels, but also has been able to delegate for the military commanders in the field, decision-making, to begin to turn the tide against the Taliban," he said.
According to the secretary of state, Afghanistan has a history of being a refuge for some of the most devastating attacks carried out.
"As we all know, the attack of 9/11 was organised and carried out from Afghanistan. So, in Afghanistan, we have to secure Afghanistan in a way that that can never occur again because there's no territory available to organisations to do so," he said.
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Tillerson asserted that Trump was clear in his speech the US was not undertaking nation-building in Afghanistan.
"They must come to some reconciliation with all ethnic groups, including the Taliban, as to how they can secure their country, as a peaceful country, one that does not support terrorism, does not provide safe havens for terrorists and does not align itself with any terrorist organisations or countries that do. That's what winning looks like," he said.
He also strongly refuted the allegation of former White House official Sebastian Gorka on the absence of word "radical Islamic terrorism" in Trump's Afghan policy speech.
"I think he's completely wrong. I think it shows a lack of understanding of the president's broader policy when it comes to protecting Americans at home and abroad from all acts of terrorism. Terrorism, as we've said, manifests itself in many types of organisation," he said.
"The president has charged us to develop policies and tactics both diplomatically and militarily to attack terrorism in as many forms, wherever it exists in the world and wherever it might present a threat to the homeland or to Americans anywhere. This means that we have to develop techniques that are global in their nature," Tillerson said.