Yemen's government has paid more than $1 million in compensation to the families of civilians killed in a 2013 U.S. drone attack on a wedding convoy, according to documents released Monday.

Yemen's tacit admission that civilians were killed contradicts repeated claims by the Obama administration that U.S. strikes spare the innocent. Experts with UK-based charity Reprieve, which obtained documents showing evidence of the compensation, say that the relatively high dollar amount from one of the poorest governments in the region indicates that the U.S. may not only know about the civilian deaths, but could be secretly funding the payouts.

According to Reprieve's evidence, which was published Monday by the Washington Post, the Yemeni government has promised to pay a total of $1.24 million in compensation for the 12 people killed in the attack, which also wounded at least 24. The documents are records of the compensation payments made to family members of all 12 people killed and bear the signatures of Yemeni court officials.

Reprieve lawyers say it is questionable that the Yemeni government, which received $256 million in U.S. aid in 2013, could have afforded the compensation on its own.

The Department of Defense last year admitted that it has documents relating to compensation for U.S. military wrongs in Yemen but refused a Freedom of Information Act request for their release, according to Reprieve.

"President Obama needs to come clean on where this money is coming from: either American taxpayers are footing the bill for his counterproductive policies, or it is falling on the shoulders of one of the world’s poorest governments,” said Kat Craig, Legal Director of international human rights charity Reprieve.

In the wake of the attack, which stoked outrage throughout Yemen and the world, anonymous U.S. officials claimed that the dead were militants. But survivors of the strikes, family members of its victims, and eye witnesses testified that the strikes in fact hit a civilian procession. A 28-page report by Human Rights Watch corroborates claims that innocent people were slaughtered in this attack.

Obama has repeatedly refused to provide a public explanation for this or other covert U.S. drone strikes that killed civilians in Yemen, Pakistan, Somalia, or Afghanistan while claiming that civilian deaths in such attacks are minimal. An initiative in the U.S. Senate to force the U.S. government to publicly report who is dying in U.S. drone strikes failed last year.

Others, however, are seeking to count the dead. The Bureau of Investigative Journalism, which has been fastidiously tracking the names of those killed in U.S. strikes, documents that in Yemen alone, up to 131 civilians were killed between 2002 and 2014 by U.S. drone strikes and up to 89 civilians were killed in other covert U.S. operations.