The alleged US drone strike that reportedly killed up to 15 people on their way to a wedding in Yemen on Thursday is just one more reason why the Obama administration has to start talking more – and more honestly – about its drone war.

Local officials in Yemen say this is the second strike this week, which has now reportedly seen the deaths of 18 Yemenis at the hands of the U.S. government, without explanation. That is unacceptable.

On Monday, a U.S. drone reportedly killed three unidentified men driving on a main road in Hadramout province. The U.S. government said nothing.

Then on Thursday, news reports indicate a convoy of vehicles traveling to a wedding in central al-Bayda province was hit by a U.S. drone that killed ten passengers instantly; another five died after arriving at the hospital. There were conflicting reports about whether suspected al Qaida “militants” were traveling in the convoy.

This time, it’s imperative that the U.S. government respond. As human rights organizations argued (again) in a letter to President Obama last week, his administration’s so-called “targeted killing” program will never be seen as lawful and legitimate if U.S. officials don’t explain what right they have to kill the people they’re targeting. In this case, where the strike apparently either missed its target or misidentified it, acknowledging the error and doing everything possible to make amends is critical to U.S. interests.

As Yemeni activist Farea al-Muslimi told The Guardian, this latest U.S. strike “saved AQAP’s image” after the group was broadly condemned for killing more than 50 people in an attack on the Yemeni defense ministry. “Nothing could have made Yemenis forget the horrible images of the attack in Sanaa more than the images of this current drone strike that targeted a wedding party,” al-Muslimi said.

Even CIA Director John Brennan has said that the United States should publicly acknowledge mistaken killings and “make public the overall numbers of civilian deaths resulting from U.S. strikes targeting al-Qa’ida.”

With the US drone campaign evidently being stepped up in Yemen, now is the time to start that practice.