President Donald Trump's most senior military and foreign policy advisers have proposed a major shift in strategy in Afghanistan that would effectively put the United States back on a war footing with the Taliban.

The new plan, which still must be approved by the President, calls for expanding the US military role as part of a broader effort to push an increasingly confident and resurgent Taliban back to the negotiating table, US officials said.

The plan comes at the end of a sweeping policy review built around the President's desire to reverse worsening security in Afghanistan and "start winning" again, said one US official, who like others spoke on the condition of anonymity to discuss internal deliberations.

The new strategy, which has the backing of top Cabinet officials, would authorise the Pentagon, not the White House, to set troop numbers in Afghanistan and give the military far broader authority to use airstrikes to target Taliban militants. It would also lift Obama-era restrictions that limited the mobility of US military advisers on the battlefield.

Advertisement

The net result of the changes would be to reverse moves by President Barack Obama to steadily limit the US military role in Afghanistan, along with the risk to American troops and the cost of the war effort, more than 15 years after US forces first arrived there.

Trump is expected to make a final call on the strategy before a May 25 Nato summit in Brussels that he plans to attend.

Officials said it was unclear whether Trump, who has spoken little about the United States' longest war, will look favourably upon expanding the US role in Afghanistan.

The new strategy is a product of the US military's mounting worries that the fragile stalemate with the Taliban has been steadily eroding for years, jeopardising the survival of an allied government and endangering a key US base for combating militant groups.