Russia has warned that any "direct aggression" by the US against the Syrian government or army would lead to “frightening, tectonic shifts” in the Middle East.
The warning by Russian Foreign Ministry spokeswoman Maria Zakharova on Saturday came after US officials said Washington had begun considering tougher responses to an ongoing Syrian assault on Aleppo, including military options.
Russia has been supporting the Syrian government in its push to take back Aleppo from terrorists.
The US is backing what it calls "moderate" militants fighting to topple Syrian President Bashar al-Assad besides carrying out airstrikes against what it calls Daesh targets.
Read more: US-led coalition kills 9 civilians in Syria
However, with Syrian advances on Aleppo gaining momentum, US officials have hinted at direct attacks on Syrian troops.
US aircraft recently bombed Syrian army positions in Dayr al-Zawr, killing 83 soldiers. The airstrike, which helped Daesh briefly overrun government positions in the area, was characterized by Washington as unintentional but Syria rejected the allegation.
"How could they (Daesh) know that the Americans are going to attack that position in order to gather their militants to attack right away and to capture it one hour after the strike?" Assad asked during an interview with the Associated Press.
Also read: Russia accuses US of sparing Jabhat Fateh al-Sham in Syria
Last week, the Middle East Eye news portal cited a source close to militants as saying that the US was resolved to prevent the fall of Aleppo.
The US State Department has warned it was considering the suspension of "bilateral engagement" in Syria unless Russia took "immediate steps to end the assault on Aleppo."
A US-Russian brokered ceasefire recently fell apart after the American airstrike on Syrian troops.
