WASHINGTON – Soon after a U.S. military drone killed about a dozen people on a remote road in central Yemen last Dec. 12, a disturbing story emerged.

Witnesses and tribal leaders said the four Hellfire missiles had hit a convoy headed to a wedding, and the Yemeni ­government paid compensation to some of the victims' families. After an investigation, Human Rights Watch charged that "some, if not all those killed and wounded were ­civilians."

Such claims are common in the U.S. drone war, and just as commonly dismissed by Obama administration officials who insist drone strikes are based on solid intelligence and produce few unintended casualties. But in this case, the CIA and the Pentagon sharply disagreed.

As a result, the Yemen attack has become fodder in a growing debate about the White House proposal for the CIA to eventually turn over its armed drones and targeted killing program to the military.

The Pentagon's Joint Special Operations Command, which carried out the December strike, insists that everyone killed or wounded in the attack was an Al-Qaida militant and therefore a lawful military ­target, U.S. officials say.

"This was not a wedding," said a congressional aide briefed by the military. "These were bad guys."

The CIA, which runs a separate drone killing program in Yemen, saw it differently.

According to two U.S. officials who would not be quoted discussing classified matters, the CIA informed JSOC before the attack that the spy agency did not have confidence in the underlying intelligence.

After the missiles hit, CIA analysts assessed that some of the victims may have been local villagers, not militants. The National Counterterrorism Center, which coordinates terrorism intelligence from multiple agencies, is somewhere in the middle, saying the evidence is inconclusive.

By all accounts, the JSOC target was Shawqi Ali Ahmad al-Badani, a mid-level leader of Al-Qaida in the Arabian Peninsula, a virulent offshoot of ­Al-Qaida.

Al-Badani, who escaped unharmed, was the alleged ringleader of plots that forced the State Department to temporarily close 19 U.S. diplomatic facilities in the Mideast and Africa last August.

The disagreement among U.S. intelligence analysts — all of whom have access to aerial video footage, communications intercepts, tips from Yemenis and other intelligence — shows that drone targeting is sometimes based on shaky evidence.

To some members of Congress, the Yemen strike shows something else: That JSOC is not as careful as the CIA, and shouldn't be given responsibility for drone killings.

Yemen's government apparently agrees. It demanded JSOC stop drone strikes in the country, but let the CIA continue. The CIA launched three strikes last month that killed up to 67 people.

"The amount of time that goes into a strike package at CIA is longer and more detailed than a strike package put together" at the Defense Department, said the same congressional aide. "Their standards of who is a combatant are different. Standards for collateral damage are ­different."

Pentagon officials dispute that, saying JSOC follows the policy President Obama disclosed in a speech last May. It bars drone strikes unless there is a "near certainty" that civilians won't be killed.

Sen. Dianne Feinstein, D-Calif., who chairs the Senate intelligence committee, recently inserted language in the classified annex of a spending bill to limit any attempts to transition the drone program from the CIA to the military.

In March 2013, long before the Yemen incident, she praised the CIA's "patience and discretion" in carrying out drone strikes. "The military program has not done that nearly as well. That causes me concern," she said.

The drones are controversial within the CIA, however. While many intelligence officers say the agency has decimated Al-Qaida with its drones, some CIA officials say the focus on killing and paramilitary operations since 2001 has diverted the spy agency from its traditional espionage mission.

The CIA, the Pentagon and the White House declined to comment for this story.

Rep. Adam Schiff, D-Calif., a member of the House intelligence committee, said he believes the military is as capable as "any other agency" in carrying out drone strikes as long as the attack is based on solid intelligence.

"At the end of the day, I don't think it matters who pulls the trigger," he said.

For now, JSOC is sharing intelligence with the Yemenis and helping them with military logistics, officials said, amid an outbreak of heavy fighting between government forces and Al-Qaida fighters.

U.S. intelligence officials say the military and the CIA have cooperated in backing a Yemeni military offensive that has driven the militants from strongholds in the south.