The U.S. had access to records of Saudi-led coalition’s airstrikes in Yemen, and Saudis “often ignored” no-strike lists provided by Washington, The New York Times reported.

“A former senior State Department official said that the United States had access to records of every airstrike over Yemen since the early days of the war, including the warplane and munitions used,” the NYT reported in an article, titled Arms Sales to Saudis Leave American Fingerprints on Yemen’s Carnage, published on Tuesday.

It said “American fingerprints are all over the air war in Yemen,” where the strikes killed over 4,600 civilians.

Yemen has been dogged by conflict since 2014, when Houthi rebels overran much of the country, including the capital Sana’a, forcing the government to take up temporary residence in the coastal city of Aden.

In 2015, Saudi Arabia and several of its Arab allies launched a massive air campaign in Yemen aimed at rolling back Houthi gains.

“At the same time, American efforts to advise the Saudis on how to protect civilians often came to naught. The Saudis whitewashed an American-sponsored initiative to investigate errant airstrikes and often ignored a voluminous no-strike list,” it reported.

According to the article, Tom Malinowski, a former assistant sectary of state, said the Saudis were given “specific coordinates of targets” that should not be struck but they continued to strike those targets.

“That struck me as a willful disregard of advice they were getting,” Malinowski was quoted as saying. “In the end, we concluded that they were just not willing to listen,” he added.

However, the U.S. military continued its support for the airstrikes, the article read.