The Russian offer, passed on through a confidential communication channel between the militaries of the two nations, was initially reported by Reuters on Sunday after the agency obtained a US government memo about it.

The Russian Ministry of Defense has now confirmed that a proposal to join efforts in Syria was sent by the chief of the Russian General Staff, General Valery Gerasimov, to the chairman of the US Joint Chiefs of Staff, US Marine General Joseph Dunford, in mid-July.

Regarding the leak, Moscow said “the inability of the US side to comply with the agreement on publicizing the contacts [between the two militaries] only with the consent of both sides is disappointing.”

“We expect that the US side will be able to take the necessary measures to prevent further violations of mutual agreements in the future.”

The Russian MoD also expanded on the content of its offer. Moscow is open “to work with the Syrian authorities on providing security guarantees to the refugees from the Rukban camp in the US-controlled area of al-Tanf and creating necessary conditions for their return home.”

The defense ministry also said it is prepared to “coordinate the issues of humanitarian demining, including in Raqqa,” as well as addressing other humanitarian issues. The joint work would serve to establish a return to peaceful life in Syria as well as curbing attempts by terrorists to find recruits.

Moscow again underlined the importance of the secure communication channel with Washington on Syria, saying that it “helps [in] preventing incidents between our armed forces and finding mutually acceptable solutions [to pressing issues], taking into account the interests of both countries.”

READ MORE: White Helmets boss denies terror links, spreads whataboutism in contentious RT interview

The Russian proposal “received an icy reception in Washington,” Reuters reported. When asked to comment on the confidential channel with the Russian military by Reuters, US Joint Chiefs of Staff spokeswoman Paula Dunn said, “In accordance with past practice, both Generals have agreed to keep the details of their conversations private.”

The UN earlier estimated that rebuilding Syria after seven years of conflict will require at least $250 billion.

Subscribe to RT newsletter to get stories the mainstream media won’t tell you.