The decision to deploy US troops to Syria in recent weeks was led not by the White House, nor the Pentagon, but by individual generals empowered by a Trump administration that has put an unprecedented amount of trust in the military brass since the war against ISIS began nearly three years ago, two defense officials told BuzzFeed News.

The manner in which the deployments — the first known of conventional forces to Syria — was undertaken marked a stark contrast to the Obama administration. Then, Army Lt. Gen. Stephen Townsend, the commander of the war against ISIS, had to get sign-off from the White House about the precise number of troops and weapons he wanted to use. With the current deployment, the Trump administration has just left it to him to determine what he needs in Syria. That is, it appears the administration signed off on the ground combat missions but so far has left the details of how to carry out that mission — including those details the Obama White House demanded — to the commander.

The change has yet to be stated officially, and some inside the chain of command are unsure if this reflects a new approach or a new administration that has yet to iron out its process and staffing. President Donald Trump has shown great deference to those in uniform, from Secretary of Defense Jim Mattis, a retired Marine general, on down.

“It’s unclear where exactly each authority lies at this point in the new administration,” one defense official told BuzzFeed News.

Last week the US military said it had deployed roughly 100 troops around the Syrian city of Manbij to mitigate skirmishes between between two opposing forces, Kurds and Turks, who have been at odds for decades. The Pentagon said Monday that the troops had been successful in stopping the skirmishes, but officials could not say how long those troops would remain in Manbij. Reports this weekend said the US military had expanded its footprint outside Manbij.

A few days later, several hundred Marines entered Syria and moved north of Raqqa, ISIS’s de facto capital, to provide artillery support for the yet-to-be-determined local forces that will be tasked with fighting the group. The Pentagon has yet to say how many troops are in Raqqa, how much artillery they brought, or how close they could be to the front lines in the battle for the city. The additional troops double the number of US forces in Syria, largely Special Forces tasked with training local fighters.

While some in the Pentagon saw the new deployments as a commander in chief trusting his generals, others are quietly uncomfortable with the US military entering another country uninvited. The administration has not sought a new Authorization for the Use of Military Force, known as an AUMF, in its war against ISIS, and includes nearly all deployments under the AUMF issued in 2001 in the wake of 9/11. Moreover, it is unclear what a defeat of ISIS, both a self-proclaimed state and also an insurgency, would look like.

“I’ll be honest. It makes me nervous,” a second defense official said.

Critics argue it adds another layer of uncertainty in an already ambiguous war. The Trump administration has called for the defeat of ISIS, but defining what that looks like has already changed since Trump took office. Up until the final days of the Obama administration, US officials said the fall of Raqqa would mark the fall of ISIS.

In anticipation of the battle for Raqqa, ISIS has begun moving its bureaucrats and leaders out of the city and toward other safe havens, the Pentagon has said. Because of that, Raqqa will likely not be the last battle against ISIS in Syria, a US defense official told reporters during a briefing last week.

In Iraq, Iraqi forces, with the backing of US troops and coalition airstrikes, are in the midst of a battle for western Mosul, after taking about 100 days to reclaim the east of the city from ISIS. US military officials suggested that after Mosul, Iraqi forces will try to take back the ISIS controlled cities of Tal Afar and Hawija.

“There seem to be a series of ad hoc plans,” Thomas Joscelyn, a senior fellow at the Foundation for Defense of Democracies and the senior editor for the FDD's Long War Journal, told BuzzFeed News.

Officially, there are 503 US troops in Syria, according to the Pentagon, largely Special Forces operators who have been training local opposition troops. And while the recent deployment doubled the official figure, there still are hundreds more not counted in the official number but rather considered to be on a temporary deployment and therefore not included in the total. This makes the US footprint appear smaller to the public.

The artillery deployed north of Raqqa, along with ongoing airstrikes, are intended to support local forces opposed to both ISIS and the Syrian regime who would lead the campaign to reclaim Raqqa, which is still “a few weeks away,” according to US backed local forces. The US military built a similar outpost outside of the Iraqi city of Mosul, ISIS’s capital in that country, in the months leading up to the offensive there. As Iraqi forces moved through eastern Mosul, the US troops moved closer to the front lines of the war there.

But there is a big difference between what happened in Mosul and what’s happening in Raqqa.

The US military is in Iraq at the invitation of the Iraqi government. In Syria, such an invitation is not clearly obtained as it is a broken state. The US military is in parts of Syria at the invitation of Kurdish forces that control those parts of the country. During an interview last week with Phoenix TV, a Chinese media outlet, Syrian President Bashar al-Assad called the US military “invaders” of Manbij.

"Any foreign troops coming to Syria without our invitation or consultation or permission, they are invaders, whether they are American, Turkish, or any other one," Assad said. "And we don't think this is going to help. What are they going to do? To fight ISIS? The Americans lost nearly every war. They lost in Iraq, they had to withdraw at the end. Even in Somalia, let alone Vietnam in the past and Afghanistan, your neighboring country. They didn't succeed anywhere they sent troops — they only create a mess."

Neither the administration nor the Pentagon announced the movement of Marines north of Raqqa; instead it leaked out and only became public through a Washington Post story that went online as troops were arriving in Syria. US military officials said that keeping the troop movement unannounced was by design to surprise the enemy. Last year, the US military did not say anything about the deployment of Marines outside the Iraqi city of Mosul until it announced the death of Marine Staff Sgt. Louis Cardin, who was part of the mission. Cardin died when the outpost came under attacks days after his arrival.

So far, the Marines stationed north of Raqqa have yet to launch artillery, the Pentagon said Monday.