If true, the battle may mark the deadliest encounter between the Cold War rivals in decades.
While the Kremlin has declined to comment, and no independent party has yet verified the reports, US and Russian aligned forces have fought on opposite sides of the Syrian conflict and in close proximity for years.
If the U.S. did kill Russian military contractors, it falls short of killing official Russian servicemembers, which could escalate into a larger war.
But the loss of Russians in Syria may still blacken the image of the Kremlin's intervention in the six-year civil war, which it portrays as peace-keeping and inexpensive.
Russian media said Russian private contractors and pro-government forces advanced on oil fields in the eastern Deir el-Zour province and were targeted by the United States.
“Pro-regime forces initiated what appeared to be a coordinated attack on Syrian Democratic Forces east of the Euphrates river,” Pentagon spokesperson Dana White said in a statement, referring to the SDF, which the US has trained, equipped, and backed for years.
The river acts as a border between the coalition and Russian and Syrian forces, and the Pentagon also described the SDF location as well-known, and that therefore the attack wasn't a mistake.
Syrian regime forces launched a coordinated attack that included about 500 regime troops, 122mm howitzers, tanks and multiple launch rocket systems on the U.S.-backed SDF headquarters in Deir al-Zor province approximately five miles east of the Euphrates River.
Navy Secretary Richard Spencer took the reins at the Pentagon on Monday, becoming the third acting defense secretary since January.
Spencer is expected to temporarily lead the Pentagon while the Senate considers Army Secretary Mark Esper's nomination to succeed James Mattis as defense secretary. The Senate officially received Esper's nomination on Monday.
U.S. Special Operations Command may be on the verge of making the dream of flying infantry soldiers a reality, but the French may very well beat them to it.
On Sunday, French President Emmanuel Macron shared an unusual video showing a man on a flying platform — widely characterized as a "hoverboard" — maneuvering through the skies above the Bastille Day celebrations in Paris armed with what appears to be a dummy firearm.
The video was accompanied with a simple message of "Fier de notre armée, moderne et innovante," which translates to "proud of our army, modern and innovative," suggesting that the French Armed Forces may be eyeing the unusual vehicle for potential military applications.
If such experiments took place, the amendment would require the inspector general's office to tell lawmakers if any of the ticks or other bugs "were released outside of any laboratory by accident or experiment design."
There's no one path to military service. For some, it's a lifelong goal, for others, it's a choice made in an instant.
For 27-year-old Marine Pvt. Atiqullah Assadi, who graduated from Marine Corps bootcamp on July 12, the decision to enlist was the culmination of a journey that began when he and his family were forced to flee their home in Afghanistan.
The Air Force has administratively separated the Nellis Air Force Base sergeant who was investigated for making racist comments about her subordinates in a video that went viral last year, Task & Purpose has learned.