The four have called for the president to rethink the country's drone warfare strategy, saying that the killing of innocent civilians in such attacks has "only fueled the feelings of hatred that ignited terrorism and groups like ISIL, while also serving as a fundamental recruitment tool similar to Guantanamo Bay."
The ex-servicemen, who have experience operating drones in Iraq and Afghanistan, criticized the tactic employed extensively by the Obama administration as being one of the most "devastating driving forces for terrorism and destabilization around the world."
The group consists of 30-year-old Brandon Bryant, former serviceman and founder of human rights activist group Project Red Hand, 29-year-old Michael Haas and Stephen Lewis, who served in Iraq and Afghanistan, and former communications technician of the drone warfare program Cian Westmoreland, 28.
Questions Over Drone Warfare Precision
While US officials have said that the use on non-manned drone warfare is a highly effective and low risk way of conducting strikes on strategic targets, others have been highly skeptical about the precision and effectiveness of drone strikes.
The recent US bombing of a Medecins Sans Frontieres (MSF) hospital in Kunduz, Afghanistan, although carried out by aircraft, led many to question the effectiveness of the overall US strategy.
Officially, Washington has only publicly admitted to killing two civilians in its air campaign in Syria and Iraq, however many believe the number is far higher.
Airwars, a project aimed at tracking the international coalition's campaign against jihadists in Iraq and Syria, has conservatively estimated that between 653 and 932 civilian non-combatants are likely to have been killed in airstrikes. Airways has also stated that it believes such actions could boost the support of terrorist groups.
"Almost all claims of noncombatant deaths from alleged coalition strikes emerge within 24 hours — with graphic images of reported victims often widely disseminated. In this context, the present coalition policy of downplaying or denying all claims of noncombatant fatalities makes little sense, and risks handing the Islamic State [ISIL] and other forces a powerful propaganda tool."
This was backed up by documents leaked in the The Intercept, which found that up to 90 percent of the people killed in US drone strikes may be unintended deaths, with many unknown victims being recorded as "enemies killed in action."
US 'Publicly Lied' About Drone Effectiveness
Meanwhile, the four ex-servicemen criticized the US government's approach and reaction to the ongoing drone campaign and called on officials to call off their pursuit and/or incarceration of fellow whistleblowers Chelsea Manning, Julian Assange and Edward Snowden.
"We witnessed gross waste, mismanagement, abuses of power, and our country's leaders lying publicly about the effectiveness of the drone program."
The comments come in the wake of the Paris terror attacks, where 129 people were killed by jihadists in a series of coordinated attacks in the French capital.
"We cannot sit silently by and witness tragedies like the attacks in Paris, knowing the devastating effects the drone program has overseas and at home."
While being established as a tactic before Obama became president, the use of lethal airstrikes has significantly increased under his administration, with the Pentagon announcing plans to increase the number of daily drone flights by 50 percent over the next four years.