The Islamic State (IS) group is in an "initial exploratory phase" and is looking for ways to expand in Afghanistan, the Pentagon has said in a report to Congress.
IS extremists have never formally acknowledged having a presence in Afghanistan.
But fears are growing that the group is making inroads there to the point that the Taliban, still Afghanistan's dominant militant Muslim group, told them to butt out.
On June 16, the Taliban warned IS against waging a parallel insurgency in Afghanistan, after a string of defections and reported clashes with militants loyal to IS.
The June 17 Pentagon report cited "evidence of limited recruiting efforts" by IS, but said its "presence and influence in Afghanistan remains in the initial exploratory phase."
IS "will likely continue to try to expand its presence in Afghanistan during the upcoming year, and it will compete for relevance with the Taliban and other extant terrorist and insurgent groups," the report said.
While the emergence of IS has "sharply focused" Afghan leaders, the report said the Taliban's strength should not be underestimated and the Haqqani network remains the biggest threat.
Based in Pakistan, Haqqani continues to be a "critical enabler" of Al-Qaeda, it said.
"The Haqqani network and affiliated groups share the goals of expelling U.S. and coalition forces, overthrowing the Afghan government, and reestablishing an Islamic Emirate of Afghanistan," the report said
"The Haqqani network led the insurgency in the eastern Afghan provinces of Paktika, Paktiya, and Khost, and demonstrated the capability and intent to support and launch high-profile, complex attacks across the country and in the Kabul region."
There are probably fewer than 100 Al-Qaeda members in Afghanistan on a full-time basis, and they remain focused mainly on survival, rather than planning future attacks on the United States, the report said.
The remaining members are concentrated largely in the eastern provinces of Kunar and Nuristan, but receive support from the Taliban and "at least tacit support" from some civilians.
Al-Qaeda fighters began to move into other provinces, including Ghazni, Zabul, and Wardak, in the spring and summer, the Pentagon said.
With reporting by AFP and The Washington Post