The US has quietly stepped up secrecy over its air wars in Afghanistan and Yemen since President Donald Trump entered office.

The American Civil Liberties Union called the new practices – discovered by the Bureau through interviews with past and present US military officials – "deeply disturbing”.

Towards the end of the Obama administration, US military officials began to communicate in a more transparent way with the Bureau about their counterterrorism campaigns. For over a year, the Bureau received detailed monthly reports on air strikes in Afghanistan, broken down into different types of strike.

The Pentagon’s Central Command (CENTCOM), meanwhile, announced its intention to launch a monthly tally of strikes in Yemen. Although this was abandoned shortly after Trump took office, Centcom continued to provide detailed information on Yemen strikes on an ad hoc basis.

By the end of 2017, specifics had started to fade out from the US military’s communications on Yemen and Afghanistan. Officials from Resolute Support, the US mission in Afghanistan, said that the Bureau would have to rely on data simply showing the number of weapons released in Afghanistan, which provides a much less clear picture of the war. A spokesman for Resolute Report explained that they no longer wanted to give so much detail to the enemy.

In February this year, a Centcom spokesman responded to a request for information on the location and casualty estimates of a spate of strikes in Yemen with a press release which simply stated the number of strikes that had occurred. The spokesman said he had been “advised” not to give out detailed information on strikes. “Secretary Mattis has made it clear we are not providing numbers or tactics that gives our adversaries any advantage”, the spokesperson said.