NEW YORK - President Barack Obama has secretly signed an order that expands the United States’ direct combat role in Afghanistan throughout 2015, a leading American newspaper reported.

Signed over the last few weeks, The New York Times said the classified order permits American forces to continue to battle the Taliban and other militants that pose a threat to either the Afghan government or US personnel. US jets, bombers, and drones will be able to aid ground troops – be they Afghan or US forces – in whatever mission they undertake, it said.

Under the order, ground troops could join Afghan troops on missions, and airstrikes could be carried out in their support.

In May, President Obama said US forces would not be involved in combat operations once the new year begins, and they would continue training Afghan forces and track down remaining Al-Qaeda members.

Obama signed the secret order after tense debates within the administration, according to the newspaper. The military reportedly argued that it would allow the US to keep the pressure on the Taliban and other groups should details emerge that they are planning to attack American troops. Civilian aides, meanwhile, said the role of combat troops should be limited to counter-terror missions against Al-Qaeda.

The Times said an administration official painted the secret order's authorisation as a win for the military, but another said the US would not carry out "offensive missions" against the Taliban in 2015.

“We will no longer target belligerents solely because they are members of the Taliban,” the official said. “To the extent that Taliban members directly threaten the United States and coalition forces in Afghanistan or provide direct support to Al-Qaeda, however, we will take appropriate measures to keep Americans safe.”

The change in direction came as the administration faces pointed criticism from those who say the US withdrew from Iraq too quickly, allowing the so-called Islamic State to make rapid gains in a country whose military proved to be easily intimidated and defeated.

Previously, the president had said US-led NATO combat operations would finish at the end of this year. The NATO follow up mission, to take over on January 1 with 9,800 US troops and about 3,000 soldiers from Germany, Italy and other member nations, was to focus on supporting Afghan forces as they take on the Taliban, in parallel with US counter-terrorism operations.But in a strategic shift, Obama signed an order. The new order also allows for air support.

The newspaper said civilian advisors argued against the broader mission for 2015, objecting to putting American lives in danger in the fight against the Taliban and recommending a narrower, counter-terrorism focus against Al-Qaeda. "There was a school of thought that wanted the mission to be very limited, focused solely on Al-Qaeda," one American official told the paper.

But, the official said, "the military pretty much got what it wanted."

Earlier this month, US defense officials had said commanders were weighing a delay in withdrawing American troops from Afghanistan after the country's protracted election set back preparations for the transition. The new head of the NATO-led force in Afghanistan, General John Campbell, and other senior officers were reviewing whether a larger force needs to stay in place longer than initially planned, officials said. At its peak, the US force rose to more than 100,000 in Afghanistan, and there are now 27,000 troops deployed.

Meanwhile, new Afghan President Ashraf Ghani has a much softer position on the US presence in his country compared to his predecessor Hamid Karzai. Ghani reportedly asked the US to keep battling the Taliban into 2015. He also removed restrictions against US airstrikes and joint raids that were implemented by Karzai.

There will be 9,800 soldiers left throughout next year, and that number will be cut in half by the end of the year. By the end of 2016, the remaining troops are scheduled to leave Afghanistan, ending the US military presence in the country.

The Pentagon plans to take the lead role in advising and training Afghan forces in southern and eastern Afghanistan, with Italy also operating in the east, Germany in the north and Turkey in Kabul.

America’s NATO allies are expected to keep about 4,000 troops of their own in Afghanistan in 2015. The allies are expected to follow the American lead in consolidating and withdrawing their troops.

The United States could still have military advisers in Kabul after 2016 who would work out of an office of security cooperation at the United States Embassy. But the administration has not said how large that contingent might be and what its exact mission would be.