US Senate Armed Services Committee Chairman John McCain who has been critical of US President Donald Trump's previous failure to articulate a strategy, said the president took "a big step in the right direction" during his speech.

He called Trump's new strategy in Afghanistan a major shift from "arbitrary timetables" for American involvement to a conditions-based approach in the region.

"I believe the President is now moving us well beyond the prior administration's failed strategy of merely postponing defeat," McCain said in a statement, noting that Trump now faces the task of keeping "the right level of effort, in the right places, with the right authorities and resources to see this conflict through to success."

"To do this, the President must conduct himself as a wartime commander-in-chief. He must speak regularly to the American people, and to those waging this war on their behalf, about why we are fighting, why the additional sacrifices are worth it, and how we will success," said McCain.

This comes hours after, the US president announced his administration’s new strategy on Afghanistan and South Asia.

After paying tribute to the US forces in Afghanistan, Trump said “I am here tonight to lay out our path forward in Afghanistan and South Asia.”

He was expected to talk about number of US troops which will be deployed to Afghanistan based on the new strategy. However, he did not mention this matter in his speech.

“We will not talk about numbers of troops or our plans for further military activities,” he said. “America's enemies must never know our plans or believe they can wait us out. I will not say when we are going to attack, but attack we will.”

Trump admitted Monday that his position on Afghanistan changed as he began to grasp his duties as president.

A Republicans Senator Paul Ryan quoted by CNN said he was actually pleased with the way Trump went about making this decision.