U.S. Joint Chiefs of Staff Chairman Joseph Dunford, Russian Chief of the General Staff Valery Gerasimov and Turkey's Chief of the General Staff Hulusi Akar are discussing "joint issues related to regional security, including Syria and Iraq", in the southern Turkish city of Antalya, the Turkish military said in a statement on its website.
Russian Federation and Turkey also coordinated their operations against the Islamic State terror group in Syria.
Turkish president Recep Tayyip Erdogan sought to build co-operation with Russian leader Vladimir Putin on Friday over military operations in Syria, as Turkey attempts to create a border "safe zone" free of Islamic State and the Kurdish YPG militia.
Friday's meeting came in the wake of the summit between the top military brass from Russia, Turkey and the United States.
The talks in Moscow also focused on how to help assuage mutual mistrust between Turkish-backed Syrian opposition forces, US-backed Kurdish forces, and Russian-allied Syrian government forces all fighting their way toward ISIL's de facto capital of Raqqa.
Russian Federation is cautiously optimistic on the chances for a peace deal in Syria, President Vladimir Putin said on Friday, after talks with Turkey's Tayyip Erdogan in Moscow.
Earlier this week, the chief military officers of Russian Federation, the United States and Turkey met in the Turkish city of Antalya in an apparent attempt to work out additional steps to prevent future accidental deaths involving each other's troops.
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The two nations also strengthened commercial and other connections.
Other documents concern holding the bilateral year of culture and tourism in 2019, cooperation between the Prosecutor General's Office and the Turkish Ministry of Justice, cooperation in the small and medium-sized business sector and cooperation between the news agencies of the two countries.
Turkey has been looking to buy a long-range missile defence system since 2013 and Turkish media reported in November that Moscow had submitted an initial offer.
Despite the rapprochement, Russian Federation has moved gradually to lift economic restrictions, keeping some in place as an apparent motivator for Turkey.
Turkish, Kurdish, Russian and Syrian regime forces have converged on the northern city, which Kurdish forces took from ISIS last August. Moscow has also offered to build Turkey a nuclear power plant at Akkuyu.
Erdogan also called the meetings in Astana, Kazakhstan where the Syrian ceasefire was agreed earlier this year "an additional factor, making the process launched in Geneva more effective". Both projects were suspended amid the escalated tensions at the end of 2015.
Erdogan, in turn, noted that defense industry and energy are among main elements of cooperation between economies of two countries.