Relations between US and UN strained over Afghanistan war reports

Relations between US and UN strained over Afghanistan war reports | World news | The Guardian: 
In a recent incident, the most senior US commander in Afghanistan, Gen John W Nicholson, considered banning or restricting the UN’s access to a military base in Kabul, according to informed sources in both organisations.
The dispute followed a UN report in late September claiming that a US drone had killed 15 civilians. Washington insists it only killed members of Islamic State.
UN and US military officials declined to speak to the Guardian, but various sources confirmed that working relations were “a nightmare”, as a UN staff member put it.