Russia and the United States are on the brink of forming a military alliance to carry out joint operations in Syria, Moscow claimed on Monday.
“We are now in a very active phase of negotiations with our American colleagues,” Sergei Shoigu, the Russian defence minister, said in comments broadcast on state television.
“We are moving step by step closer to a plan – and I’m only talking about Aleppo here – that would really allow us to start fighting together to bring peace so that people can return to their homes in this troubled land,” he said.
US officials played down Mr Shoigu’s comments, however.
“We have seen press reports of the Russian Defense Minister’s comments,” a state department official told The Telegraph, adding that they have “nothing to announce at this time.”
“We speak regularly with Russian officials about ways to strengthen the cessation of hostilities, improve humanitarian access, and bring about the conditions necessary to find a political solution to this conflict,” the official added.
The United States is believed to have offered Russia a military alliance against groups both countries consider terrorists last month.
The proposed deal, laid out in a document leaked to the Washington Post, would see the countries working together to attack Islamic State of Iraq and the Levant (Isil), but also al-Qaeda-aligned Jabhat al-Nusra jihadists, who have been locked in fierce battles with the regime.
The proposals were controversial because the former Cold War foes currently support opposing sides in the conflict, with Russia bombing in support of the Syrian government, and the US arming and training rebels.
The nascent deal was further strained last month after it emerged Russia bombed a base used by British and US special forces in June.
Jabhat al-Nusra cut its ties with al-Qaeda and renamed itself Jabhat Fatah al-Sham in late July, in a rebranding effort apparently intended to deflect pressure from Washington and Moscow.
The group is playing a key role in the intensifying battle for Aleppo, the north western city that has been a stronghold of the anti-Assad uprising since war broke out in 2011.
Regime backed troops backed by Russian airstrikes managed to encircle the opposition-held eastern half of the city a month ago, but their siege was shattered by a rebel counter attack a week ago.
Syrian government forces said they repelled a renewed rebel attack southwest of the city on Monday and forced opposition forces to relinquish gains they made the previous day, in the latest of a series of back-and-forth struggles around the city.
The United Nations has warned of a looming humanitarian disaster in the city, where up to two million people are believed to have been left without running water. Up to 300,000 people trapped in rebel-held eastern Aleppo are believed to be running short of food and other essentials.
Peter Maurer, the head of the International Committee of the Red Cross, on Monday called the battle for Aleppo “one of the most devastating urban conflicts in modern times.”
Victory in Aleppo would be a triumph for Mr Assad and deal a potentially knock-out blow to the opposition.
A rebel victory would be the first serious set back suffered by the regime since Russia entered the war in September 2015 and could reinvigorate the opposition cause.
“Aleppo is one of the turning points,” said Fyodor Lukyanov, the head of the council on foreign and defence policy, a think tank close to the Russian foreign policy establishment. “I am sure Russia will do everything it can to guarantee that the dynamics of the war cannot be changed.”