Afghan forces and North Atlantic Treaty Organisation and USA -led coalition troops continued in mopping-up operations as the Taliban militant group has been attempting to take territory and consolidate its positions ahead of winter in the Central Asian country.
The Afghan Government hardly controls 55.5 percent of its territory, the lowest level in three years, the United States, whose troops are deployed here since the invasion in 2001, warned on Thursday.
The SIGAR noted that 65 percent of the Afghan population lives in those districts, which are most influenced by the administration of President Ashraf Ghani.
Afghanistan is experiencing a situation of political and social instability and insecurity due to the intervention of USA troops and its North Atlantic Treaty Organisation allies.
"Since SIGAR began receiving district-control data in November 2015, Afghan government control and influence over its districts has declined by about 16 percentage points; contested districts have increased by about 11 points; and insurgent control or influence has risen by 5.5 points", the watchdog reiterated.
General John Nicholson, who is now retired but at the time was head of Resolute Support, said in November 2017 that the Afghan security forces would expand control of the population to 80 percent over the next two years. The balance - 132 districts - are considered "contested" between the government and insurgent groups.
Bill Roggio, an Afghanistan expert and senior fellow at the Foundation for Defense of Democracies, told AFP such a scenario is unlikely.
This year broadly has also proved to be the deadliest for Afghan civilians.
The report also cited last month's attack in Kandahar that killed the regional police and intelligence chief.
He escaped unhurt, but US Brigadier General Jeffrey Smiley was among 13 people wounded in the shooting, which the Taliban said had targeted Miller and Raziq.
Although the USA agreed last year to classify the number of Afghan casualties, more than 5,000 have been killed each year according to figures SIGAR published before the blackout.
The Taliban have still not succeeded in taking a major provincial center despite assaults on the provinces of Farah and Ghazni this year, but they control large parts of the countryside, the SIGAR report says.
This comes after the US Defense Secretary James Mattis said Tuesday that Afghan forces suffered 1,000 casualties in August and September.
SIGAR added that data show the Afghan forces "made minimal or no progress in pressuring the Taliban over the quarter".