Reports in Russian media have said Wagner - a shadowy organization known as Russia's answer to Blackwater - was hired by Assad or his allies to guard Syrian energy assets in exchange for oil concessions.
The incident appears to be the first publicly known case of the US military firing on and killing Russians fighting on behalf of Syrian President Bashar al-Assad.
Lt. Gen. Jeffrey Harrigian says the drone saw the tank "that took a shot at us", and that he believes the USA rules of engagement allowed for the tank to be destroyed in self-defense to protect the drone. Three people within were killed. "We don't have data about other Russians who could be in Syria".
Pro-Assad fighters approached the US-held base in a "battalion-sized formation supported by artillery, tanks, multiple-launch rocket systems and mortars" on 7 February, Col Thomas F Veale, a spokesman for the United States military, said in a statement.
The officials said the US was puzzled because proper procedures had been followed - American forces used the deconfliction line to get Russia's go-ahead to defend coalition forces against the attackers.
THIS is the moment an American warplane locks on to a Russian tank in Syria and blows it to bits within an instant.
Russian forces are supporting the Syrian government in its war with opposition groups, some of which are backed by the United States. He called on Putin to report publicly about "the actions of Russian troops in Syria at present and the number of deaths of Russian citizens regardless of their military status".
Military.com says the drone attack was carried out in "self-defense" after forces loyal to President Bashar al-Assad fired at USA advisers and allied Syrian fighters.
Kremlin spokesman Dmitry Peskov declined to comment on the incident, in which the death toll of private Russian soldiers may have been five times greater than the Russian Defense Ministry's official count of servicemen who have died in Syria.
The Russian newspaper Novaya Gazeta said 13 Russians were killed in the attack and another 15 wounded.
The death of Russians under direct American, or at least US-led fire would seem a very serious matter.
US Defence Secretary Jim Mattis played down the incident, saying: "This could just be a local couple of guys doing something".
The officials also said it wasn't clear whose fighters made up the attacking force.
Mattis also doubted that the Russians control the situation in the region. One Syrian officer claimed that as many as 100 Russians were killed over two days of fighting, but the Kremlin has been slow to respond to such claims.
As the main global backer of Syrian President Bashar al-Assad's regime, Russian Federation has committed itself to aiding in the country's reconstruction. There were no coalition or SDF casualties, Dillon said.
One thing is clear both Mr Putin and U.S. officials will face pressure to be transparent about such clashes.
The award-winning actor took out a full-page ad in the Austin American-Statesman to let acknowledge Foles for his accomplishment. John Bridges, the managing editor of the paper, tweeted out a photo of the ad, as did sports reporter Brian Davis.
A spokesman for the Kurdish militia, Mustafa Bali, said his fighters brought down the aircraft in Raju, north-west Afrin. He said Erdogan and the Turkish media were "trying to cover the Turkish army's failure in Afrin".
GoDaddy made a decision to rejoin Patrick for her final two races, and she reached out to Eury to set up her Daytona ride. But the No. 7 Chevrolet is here only for the Great American Race, a fact that Patrick recently was lamenting.
Omarosa Manigault has been sent to the hospital early this morning while on the show Celebrity Big Brother . During the competition, Marissa Jaret Winokur knocked Omarosa out , and the latter suffered an injury.
In a map proposed by Republicans she would instead be drawn into the 7th Congressional District, based in Delaware County. The districts limit splits dramatically. "Where you make the splits is where the art of the gerrymander lies", Wang said.
But after winning the US junior title in 2015, she dropped off the competitive radar while dealing with a series of injuries. Tennell turned 20 at the end of January, just after she won her first US national championship title.
The low on Tuesday was 1 below, 14 degrees below normal and 18 degrees above the record low of 19 below for the date, set in 1977. It has the potential to bring up to a foot of thick, wet snow to the region before it departs early Saturday morning.
However, settling scores with their detractors is not his first priority ahead of Les Bleus' visit to Murrayfield on Sunday. Missing touch from a penalty saps any kind of confidence from a team and is fundamentally inexcusable at the highest level.
Rise in USA oil rigs push Brent oil below $62
On Thursday, it closed down 64 cents, or 1 percent, to settle at $61.15, its lowest close since January 2. The additions put the USA oil rig count at 791, which is the highest it has been since April 2015.
Gerald Stanley found not guilty of second degree murder
Pratt said. "We commit to the spirit of love, we commit to the spirit of change and we commit to a spirit of growth". Trudeau addressed the case Saturday at a news conference in Los Angeles, where he was wrapping up a trip to the U.S.
Antonio Conte anxious key player may not return this season
The Blues signed Olivier Giroud from Arsenal during the transfer window, but he's still yet to make his first start for Chelsea . West Brom's Jay Rodriguez has been charged by the FA for allegedly making racist comments to Brighton defender Gaetan Bong.