The Obama administration has expanded its legal authority to attack the al-Qaida-linked Somali militant group al-Shabab.

Citing senior U.S. officials, The New York Times reported Monday the administration has deemed al-Shabab to be part of the armed conflict that Congress authorized against the perpetrators of the September 11, 2001 attacks.

The move, the paper said, has some legal and foreign policy experts concerned the administration is overexpanding its authority to cover counter-terrorism operations in countries far from Afghanistan.

It will also strengthen future president Donald Trump's authority to combat thousands of Islamist militants in the Horn of Africa nation, the paper said.

The U.S. has carried out numerous airstrikes aimed at al-Shabab leaders, including one that killed the group's top leader, Ahmed Abdi Godane, in 2014. There are also a small number of U.S. intelligence and military personnel on the ground, helping Somali government and African Union troops battle al-Shabab.

Council on Foreign Relations senior fellow Micah Zenko told the Times, "It is crazy that a piece of legislation that was grounded specifically in the experience of 9/11 is now being repurposed for close air support for regional security forces in Somalia."

The Authorization for the Use of Military Force (AUMF) against Al-Qaeda, approved by Congress in 2001, was passed in the days following the 9/11 terror attacks against the World Trade Center in New York and the Pentagon.

But President Barack Obama’s top counterterrorism adviser Lisa Monaco said the terrorism threat “is constantly evolving and requires an adaptable response.”

Monaco added that the administration “recognizes that we must more effectively partner with countries where terrorist networks take hold, enabling and empowering these partners to share the burden of combating these threats tour mutual interests.”

Al-Shabab has been fighting since 2006 to overthrow the Somali government and establish a state based on the group's strict version of Islamic law. The group became an al-Qaida affiliate in 2012.