Kabul: The Obama administration has granted the military new authority to strike the Daesh group in Afghanistan, signalling a more sustained fight against the extremist group outside of its base in Iraq and Syria, officials said on Wednesday.

A defence official, speaking on the condition of anonymity to discuss internal decisions, said new rules of engagement approved last week permit US commanders in Afghanistan to launch air strikes against militants affiliated with Daesh, in the same way that the military targets fighters linked to Al Qaida.

The new arrangement “enables the United States to more actively target Daesh in Afghanistan,” the official said, using an acronym for the group that controls parts of Iraq and Syria and has established outposts from North Africa to Central Asia.

Under previous rules, the US military was able to conduct air strikes in Afghanistan in three circumstances: to protect foreign forces; to help Afghan troops ward off an enemy onslaught; and to target Al Qaida and affiliated militants.

According to a second official, who also spoke on the condition of anonymity, the US military has struck militants identified with the Daesh in Afghanistan in the past, but those strikes were launched on the basis of the fighters’ “hostile intentions” rather than their affiliation with the group’s Afghan organisation. The new rules were first reported by the Wall Street Journal.

While the decision does not signal a dramatic change for US activities in Afghanistan, it strengthens commanders’ authority against assorted militants there and, more generally, illustrates the expanding US campaign against the Daesh beyond its home base.

The change comes as the Afghan government struggles to beat back an emboldened Taliban, whose sustained attacks have jeopardised not just ordinary Afghans, but also President Obama’s hopes of ending US military involvement in Afghanistan before he leaves office. Amid worsening security across Afghanistan, the White House has several times altered Obama’s original plans for withdrawing US troops.

Now the country faces a new threat from militants who have aligned themselves with the Daesh and are mostly arrayed near Afghanistan’s border with Pakistan. Defence Secretary Ashton B. Carter visited Afghanistan’s eastern Nangahar province in December and discussed the growing Daesh presence there with Army Gen. John F. Campbell, the commander of US and Nato forces in Afghanistan.

Taliban and Daesh militants are battling one another for control of resources, even as both also fight government forces.

The granting of expanded strike authority follows the State Department’s designation this month of the Daesh’s Afghan entity, called “Daesh-K,” or Khorasan, as a foreign terrorist organisation.