In this 2010 photo, an unmanned U.S. Predator drone flies over Kandahar Air Field, southern Afghanistan on a moonlit night. (Kirsty Wigglesworth/AP)

A federal appeals court on Thursday dismissed a ­long-running lawsuit seeking access to more details about the U.S. government’s lethal-drone operations.

In a brief order, the U.S. Court of Appeals for the District of Columbia Circuit said the government can continue to withhold certain information about the strikes because such details “could reasonably be expected to damage national security.”

The American Civil Liberties Union (ACLU) has pressed the CIA for specific statistics about the strikes, including the dates, locations and numbers of people killed, in addition to a dozen legal memos outlining the government’s authority to carry out the operations.

The three-judge panel made up of Thomas B. Griffith, David B. Sentelle and David S. Tatel upheld a lower court ruling after reviewing a classified affidavit from a CIA official.

“The agency’s explanations as to why the records are classified are both ‘logical’ and ‘plausible’ and uncontroverted by evidence in the record,” according to the five-page order.

The unsigned order does not carry the precedent-setting weight of a formal, signed court opinion.

Jameel Jaffer, the ACLU’s deputy legal director who argued the case, called the decision a disappointment. The Obama administration, he said, should independently release redacted versions of the memos the ACLU requested in its Freedom of Information Act lawsuit filed in 2010.

“Secret law is always invidious, but it’s particularly so here because of the subject matter,” he said. “These legal memos describe the circumstances in which the CIA believes it has authority to carry out extra-judicial killings.”

After oral arguments in February, the ACLU asked the D.C. Circuit to remand the case to a lower court for further review because the administration has announced plans to disclose the number of casualties from U.S. drone strikes and other targeted killings since the president took office in 2009.

The original ACLU lawsuit requested information on all CIA drone strikes outside the active wars in Afghanistan and Iraq. The administration has long promised to release figures on civilian deaths from strikes “outside areas of active hostilities,” and Lisa Monaco, President Obama’s chief counterterrorism adviser, said in a speech last month that the information would be published “in the coming weeks.”

While the administration is likely to release information about strikes in Yemen, Somalia and perhaps Libya, its figures may not include Pakistan—where the vast majority of CIA strikes have occurred. The administration, but not the ACLU, has generally described Pakistan as part of the active war in Afghanistan.

The court essentially told the civil liberties group to wait and see what information is released by the administration and suggested that it could always file another lawsuit.

“It is not yet possible to determine whether the information the government plans to release will duplicate that being withheld or undermine the government’s assertion that disclosing summary strike data could reasonably be expected to harm national security,” the court said.

Karen DeYoung contributed to this report.