But the command did not answer several other questions: Who were the two dead militants, and why were they important enough to kill with an airstrike? What role, if any, did France play in a region of Libya in which it has also conducted counterterrorism operations? And, most significantly, to what extent is the attack the start of an escalating campaign against a broad spectrum of extremists in northwestern Africa, or a one-off strike against high-profile Qaeda operatives?

“Beginning a concerted strike campaign against AQIM or other AQ elements in the Sahel, akin to what we are doing in Yemen and Somalia, would mark a significant expansion of our counterterrorism efforts,” said Luke Hartig, a former senior director for counterterrorism at the National Security Council during the Obama administration.

“If this is going to be the start of a broader campaign, it would be helpful to hear more from the administration about the threat posed by AQIM and why it merits putting our people in harm’s way and conducting strikes,” Mr. Hartig said.

A senior French security official said France had played no role in the strike, but added that Paris was “very happy of this continued commitment of the U.S. to counterterrorism in Libya.”

Questions about whether the American military, under the Trump administration, is seeking to blur the expanding scope of operations in Africa were raised this month when it was revealed that the United States had carried out four airstrikes in Libya between September and January that Africa Command did not disclose at the time. The military has said it will acknowledge such missions if asked about them, even if it does not affirmatively disclose them in a news release.

Ms. Mack said that Saturday’s attack was the first airstrike the United States had conducted against Al Qaeda in Libya. In fact, the United States conducted an airstrike in eastern Libya in June 2015 against Mokhtar Belmokhtar, the mastermind of the 2013 terrorist seizure of an Algerian gas plant that left 38 foreign hostages dead. Mr. Belmokhtar was a longtime Qaeda operative with ties to senior Qaeda leadership in Pakistan. Western intelligence officials today remain divided over whether he is dead.

American efforts to hunt down Islamists in Libya’s vast deserts rely heavily on surveillance and airpower but also on alliances with the armed groups vying for control of Libya. Mohamed El Sallak, a spokesman for the United Nations-backed unity government, said on Twitter that the attack in Ubari on Saturday was part of the “strategic cooperation between Libya and the United States in the fight against terrorism.”