An airstrike carried out on Tuesday 26th in Libya killed "several" fighters from the Islamic State group, also known as ISIS, according to a Thursday 28th statement from U.S. Africa Command. It followed a similar UAV 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.
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.
"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."