More than three-quarters of the civilians killed during the four-year war against Isis in Iraq and Syria occurred during Donald Trump's presidency, new figures show.

A total of 831 civilians have been “unintentionally killed” over the period, according to the US military’s own figures.

Data released by the Combined Joint Task Force for Operation Inherent Resolve (CJTF-OIR) on 2 January 2017, just a few weeks before Mr Trump took office, said “it is more likely than not, at least 188 civilians have been unintentionally killed by Coalition strikes since the start” of the operation in 2014.

But that has increased significantly over the last 12 months since Mr Trump took office.

“Although the coalition takes extraordinary efforts to strike military targets in a manner that minimises the risk of civilian casualties, in some incidents casualties are unavoidable,” the task force wrote in the last report.

However, there is still an imprecise count of civilian deaths in the conflict.

The coalition has been criticised by several experts for under-counting the number of civilian deaths. It did not start issuing monthly civilian casualty numbers until March 2017.

Airwars, a journalist-led watchdog of the coalition, has said the number is closer to 6,047 civilians who have been killed since the start in 2014.

The group also said the number of airstrikes by the coalition, made up almost entirely of US planes, had increased by nearly 50 per cent in Iraq and Syria in 2017 compared with the previous year. Civilian deaths rose by 215 per cent, The Guardian reported.

Explosions as Turkey confirms airstrikes on Afrin, Syria

According to a New York Times report about civilian casualties in November, “in the effort to expel Isis from Iraq and Syria, the coalition has conducted more than 27,500 strikes to date, deploying everything from Vietnam-era B-52 bombers to modern Predator drones”.

Major Shane Huff, a spokesman for the US Central Command, told the newspaper that it is “one of the most precise air campaigns in military history”.

The coalition command did not immediately respond to a request for comment on what metrics were used to determine “credible” reports versus those that were deemed “non-credible”.

In Pictures: The crisis unfolding in Syria Show all 30 1 /30 In Pictures: The crisis unfolding in Syria In Pictures: The crisis unfolding in Syria A Syrian family arrives at a checkpoint, manned by pro-government forces, at the al-Hawoz street roundabout, after leaving Aleppo's eastern neighbourhoods Getty In Pictures: The crisis unfolding in Syria A Syrian woman, fleeing violence in the restive Bustan al-Qasr neighbourhood, reacts as she stands with her children in Aleppo's Fardos neighbourhood, after regime troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian pro-regime fighters, gesture as they drive past resident fleeing violence in the restive Bustan al-Qasr neighbourhood, in Aleppo's Fardos neighbourhood Getty In Pictures: The crisis unfolding in Syria Syrian rebels withdrew from six more neighbourhoods in their one-time bastion of east Aleppo in the face of advancing government troops, the Syrian Observatory for Human Rights said Getty In Pictures: The crisis unfolding in Syria Syrian rebels withdrew from six more neighbourhoods in their one-time bastion of east Aleppo in the face of advancing government troops, the Syrian Observatory for Human Rights said Getty In Pictures: The crisis unfolding in Syria Syrian residents, fleeing violence in the restive Bustan al-Qasr neighbourhood, arrive in Aleppo's Fardos neighbourhood , after regime troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian pro-regime fighters, gesture as they drive past residents fleeing violence in the restive Bustan al-Qasr neighbourhood, in Aleppo's Fardos neighbourhood Getty In Pictures: The crisis unfolding in Syria Syrian residents, fleeing violence in the restive Bustan al-Qasr neighbourhood, arrive in Aleppo's Fardos neighbourhood, after regime troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian residents, fleeing violence in the restive Bustan al-Qasr neighbourhood, arrive in Aleppo's Fardos neighbourhood Getty In Pictures: The crisis unfolding in Syria A Syrian pro-regime fighter speaks with a child, as residents flee violence in the restive Bustan al-Qasr neighbourhood. Syrian rebels withdrew from six more neighbourhoods in their one-time bastion of east Aleppo in the face of advancing government troops AFP/Getty Images In Pictures: The crisis unfolding in Syria Smoke rises as seen from a governement-held area of Aleppo, Syria Reuters In Pictures: The crisis unfolding in Syria Syrian soldiers targeting rebels-held areas in the eastern neighborhoods in Aleppo, Syria. According to media reports, the army is now holding on 99 percent of Aleppoís eastern neighborhoods EPA In Pictures: The crisis unfolding in Syria Syrian pro-government forces patrol Aleppo's eastern al-Salihin neighbourhood after troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian soldiers rest following the battle at al-Sheik Saeed neighborhood in Aleppo, Syria EPA In Pictures: The crisis unfolding in Syria A Syrian pro-government fighter walking past closed shops in the Bab al-Nasr district of Aleppo's Old City. Once renowned for its bustling souks, grand citadel and historic gates, Aleppo's Old City has been rendered virtually unrecognisable by some of the worst violence of Syria's war Getty In Pictures: The crisis unfolding in Syria The crucial battle for Aleppo entered its 'final phase' after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad Getty In Pictures: The crisis unfolding in Syria Syrian civilans arrive at a checkpoint, manned by pro-government forces, at the al-Hawoz street roundabout, after leaving Aleppo's eastern neighbourhoods. Syria's government has retaken at least 85 percent of east Aleppo, which fell to rebels in 2012, since beginning its operation Getty In Pictures: The crisis unfolding in Syria Syrian civilians flee the Sukkari neighbourhood towards safer rebel-held areas in southeastern Aleppo Getty In Pictures: The crisis unfolding in Syria Syrians celebrate in the government-held Mogambo neighbourhood of the northern Syrian city of Aleppo, after rebel fighters retreated into a small pocket of their former bastion in the face of new army advances Getty In Pictures: The crisis unfolding in Syria Syrians celebrate in the government-held Mogambo neighbourhood of the northern Syrian city of Aleppo, after rebel fighters retreated into a small pocket of their former bastion in the face of new army advances. The fall of Aleppo would be the worst rebel defeat since Syria's conflict began in 2011, and leave the government in control of the country's five major cities Getty In Pictures: The crisis unfolding in Syria A Syrian refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria Syrian refugee Aliya inside the tent where she lives with her husband and ten children in a camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria Syrian refugee women and children outside the entrance to their tents in the refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA Wire In Pictures: The crisis unfolding in Syria A Syrian refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria A Syrian refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA Wire In Pictures: The crisis unfolding in Syria A Syrian refugee woman outside the entrance to the tent where her family live, in the refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria A vehicle drives past a mosque at night in Idlib, Syria. Picture taken with a long exposure Reuters In Pictures: The crisis unfolding in Syria Damaged buildings stand in the rebel-controlled town of Binnish in Idlib province, Syria Reuters In Pictures: The crisis unfolding in Syria The night sky is seen through damaged windows in the rebel-controlled town of Binnish in Idlib province, Syria Reuters In Pictures: The crisis unfolding in Syria Damaged buildings stand in the rebel-controlled area of Maaret al-Numan in Idlib province, Syria Reuters

Some experts have noted that part of the issue may be Mr Trump’s lack of involvement in military operations compared to his predecessor.

In mid-April 2017, Mr Trump declared he was giving US military generals “total authorisation” to make complex decisions on the ground in conflict zones, which alarmed some national security experts who felt the lack of a civilian check on military operations would harm civilians caught in the conflict.

“We have the greatest military in the world and they’ve done a job as usual. We have given them total authorization and that’s what they’re doing and, frankly, that’s why they’ve been so successful lately,” Mr Trump said.

It was a move away from the policies of the previous Obama administration, who had been deeply involved in strategic decisions.

Democratic Senator Jack Reed told Roll Call: “By definition, he’s commander in chief so I would think that that’s not the way I would phrase delegation of authority to subordinates if I were commander in chief...It’s difficult to understand his involvement. Whether he wants to be briefed before [an operation] or briefed after or briefed at all, I don’t know.”