U.S. forces in Africa this week staged what would have been an otherwise unremarkable attack against Islamic State extremists but for one key detail: The operation was the first to rely on authorities granted under the Trump administration that allow the military to conduct lethal strikes outside a designated war zone and without explicit White House approval in advance.

An airstrike carried out on Tuesday in Libya killed "several" fighters from the Islamic State group, also known as ISIS, according to a Thursday statement from U.S. Africa Command. It followed a similar drone attack last week that Trump personally approved, the first in Libya since the one President Barack Obama authorized in January the day before he stepped down from office.

But the latest operation is unique in that it did not take place in an "area of active hostilities," a term the Obama administration used to clarify where the U.S. is and is not at war and, perhaps more importantly, where military commanders – not the president or his immediate team – would determine whether a drone strike or other deadly operation was appropriate.

The rules that governed Tuesday's strike show how much more power the military now has to determine where it can go after terrorist networks, and it follows recent reports that the administration seeks to to increase the authority of the military and the CIA to conduct drone operations.

That the military can now carry out such operations raises new questions about the general limits of its power in Africa and elsewhere: What now stops the Defense Department from carrying out drone strikes wherever it wants?

Until earlier this year, a still-classified portion of Libya was determined to be an area of active hostilities, as is still the case in a part of Somalia outside the capital, Mogadishu. Multiple sources who spoke to U.S. News confirm that designation for Libya has expired.

Trump announced in March that he would give the military more flexibility to swiftly target extremists, curbing micromanagement from the White House.

"These strikes were conducted under the Presidential Policy Guidance," Defense Department spokeswoman Army Maj. Audricia Harris says, referring to a 2014 document the Obama White House released explaining the policies that would govern covert war. "That allows for the use of all available tools of national power to protect the American people from threats posed by groups such as ISIS, al-Qaida and their associated forces."

The terrorist network, along with others like al-Qaida, is exploiting the political chaos that continues to roil the northeast African nation, AFRICOM said. The strike took place roughly 100 miles south of the coastal city of Sirte, once considered the group's " lifeboat " for thousands of fighters, including some who fled there from its so-called caliphate in Iraq and Syria.

The city was liberated by a U.S.-backed coalition at the beginning of the year. Pentagon spokesman Army Col. Robert Manning declined to say earlier this week how many fighters from the Islamic State group remain in Libya, though their numbers are believed to be around 500.

The area of active hostilities in Libya expired at the end of last year following the conclusion of Operation Odyssey Lightning, the mission name for hunting the Islamic State group in and around Sirte, according to AFRICOM spokesman Patrick Barnes. The designation was temporarily extended to allow for the strike Obama ordered for Jan. 19, the day before Trump's inauguration, and has since expired again.

As for whether the command could carry out strikes wherever it chooses in Africa, an official speaking on the condition of anonymity to discuss current operations says it limits its actions to pre-established agreements with partner countries. In this latest instance, AFRICOM coordinated with the de facto coalition governing Libya known as the Government of National Accord. It has similar arrangements with other partners in Africa, including with Somalia to hunt Islamic State group fighters and with others to combat piracy off the Horn of Africa and the Gulf of Guinea.

It's unclear, however, whether those arrangements are hard rules or simply guidelines. The White House retains the authority to carry out operations against terrorists outside war zones and without the host country's permission, as Obama demonstrated through the 2011 Navy SEAL raid into Pakistan that killed Osama Bin Laden.

Tuesday's strike is hardly the first time the U.S. has conducted covert operations against extremist fighters in Africa outside of declared combat zones. The U.S. reportedly began targeting extremists in Somalia as early as 2011, if not before.