Partially lifting the secrecy that has cloaked one of the United S...

The official civilian death count is far lower than estimates compiled by independent organizations that try to track what the government calls targeted killings, and human rights groups expressed doubts about the reliability of the government’s numbers. Most of the strikes have been carried out by drones in chaotic places like Libya, tribal Pakistan, Somalia and Yemen, though a small number have involved traditional aircraft or cruise missiles.

At the same time, President Obama issued an executive order making civilian protection a priority and requiring the government in the future to disclose the number of civilian deaths each year. The order, which could be canceled or altered by a future president, tries to commit his successors to greater openness than he has achieved in his first seven years in office.

For Mr. Obama, the drone program is personal, a defining feature of his presidency. As he expanded the use of drones far beyond what President George W. Bush had begun, he took a direct role in approving some strikes, including the deliberate killing of an American, and in setting up rules to govern them.

In a seeming acknowledgment that the long-anticipated disclosure would be greeted with skepticism by critics of the drone program, the administration issued the numbers on a Friday afternoon before a holiday weekend. The use of a range of estimated civilian deaths underscored the fact that the government often does not know for sure the affiliations of those killed.

“They’re guessing, too,” said Bill Roggio, editor of the Long War Journal at the Foundation for the Defense of Democracies, who has tracked civilian deaths for more than a decade. “Theirs may be a little more educated than my guesses. But they cannot be completely accurate.”

The disclosure about civilian deaths and the executive order, the subject of months of bureaucratic deliberations, carried broader significance. Issued about seven months before Mr. Obama leaves office, the order further institutionalized and normalized airstrikes outside conventional war zones as a routine part of 21st-century national security policy.

The order declares that “civilian casualties are a tragic and at times unavoidable consequence of the use of force in situations of armed conflict or in the exercise of a state’s inherent right of self-defense,” and lays out the “best practices” necessary to reduce their likelihood and “take appropriate steps” when they occur.

The estimated number of civilian deaths between Mr. Obama’s inauguration in 2009 and the end of 2015 was contained in a report issued by the Office of the Director of National Intell.... It said the numbers came from 473 strikes, which also killed 2,372 to 2,581 “combatants.”

Document | Obama Administration Releases Death Toll from Airstrikes The Office of the Director of National Intelligence released an official count for the number of civilian and combatant casualties from airstrikes outside of war zones from 2009 to 2015. President Obama also issued an executive order requiring the government to release an annual set of such numbers going forward. In addition, the White House released a fact sheet describing the policy.