Russia and the United States are close to starting joint military action against militants in Syria's Aleppo, Russia's TASS news agency quoted Defence Minister Sergei Shoigu as saying on Tuesday.
Fighting for control of the divided city, where some 300,000 people remain, has intensified in recent weeks and there have been some gains for opposition groups battling Syrian regime forces.
Russia has backed Syrian regime leader Bashar al Assad in the five-year-old Syrian conflict, while the United States wants to see Assad step down. But both are participating in talks to try to find a political solution to end the civil war.
Russia is now "in a very active stage of negotiations with our American colleagues, in both Geneva and Amman, and in constant contacts with Washington," the defence minister told Rossiya 24 television.
"We are step-by-step approaching an alternative, I am speaking only about Aleppo now, that will help us to find some points in common and to start actually joint fight to see peace established in that territory, on that long-suffering land, and people returning to their homes."
Asked about Shoigu's remarks, US State Department spokeswoman Elizabeth Trudeau told reporters in Washington: "We have seen the reports and have nothing to announce ... We remain in close contact (with Russian officials)."
Trudeau said the United States continued to push for a broader cessation of Syria hostilities accord with Russia.
Senior Russian and US military officials have held Geneva negotiations on Aleppo and on restoring an overall ceasefire, UN Special Envoy for Syria Staffan de Mistura said last Thursday.
"Concrete and well-organised" cooperation
The minister said cooperation of Russia and the US on the settlement in Syria was on the whole "concrete and well-organised".
He echoed Russia’s earlier requests to US counterparts to share the "moderate opposition’s" accurate coordinates in order to let the Russian aerospace group avoid hitting these areas, or to disclose the coordinates of DAESH terrorists and Nusra Front militants, both of whom are outlawed in Russia, but the Russian military has not yet received such information.
"We then put forward a different solution. Our president and the president of the United States said, yes, let’s follow a different path," Shoigu said.
"If there are those who claim they are prepared to cease fire, we may conclude separate agreements with them and remember that there are people who are ready not to lay down arms, but just for a cease fire. This whole procedure is very concrete and very well organised," he added.
The Russian defence minister said all proposals for joint efforts were aimed at preserving Syria’s territorial integrity, defeating terrorism and settling issues at the negotiating table.
Moscow and Damascus launched a joint humanitarian operation in Aleppo on July 28. Several corridors were opened to let people leave the city and to bring food, medical supplies and other essentials to the city.
The Russian General Staff later said that starting from August 11 combat operations in Aleppo would be paused for three hours a day to let humanitarian convoys enter the city.
The battle for Aleppo is "one of the most devastating urban conflicts in modern times," Peter Maurer, president of the International Committee of the Red Cross (ICRC), said on Monday.
"No one and nowhere is safe. Shellfire is constant, with houses, schools and hospitals all in the line of fire. People live in a state of fear. Children have been traumatised. The scale of the suffering is immense," Maurer said in a statement.
The ICRC reiterated its call on all warring parties to allow humanitarian agencies to deliver supplies to civilians in desperate need of food and clean water across Aleppo.