"The two military leaders will discuss the deconfliction of coalition and Russian operations in Syria, plus exchange views on the state of US-Russia military relations and the current international security situation in Europe and other key topics," Ryder said.

Since Russia's entry into the Syria conflict in 2015, Moscow and Washington have worked out their respective areas of operations against the Islamic State group, warning each other of planned air operations to avoid contact.

Issues between the US and Russian militaries also include tensions over nuclear forces in Europe, with the US renouncing the 1986 Intermediate-Range Nuclear Forces (INF) treaty, citing Russian noncompliance.

The treaty eliminated short- and medium-range ballistic missiles, cruise missiles and missile launchers from Europe.

Despite the conflict in Syria and the rising bilateral tensions, the military chiefs have kept open a channel of communications.

In August 2018, Russia sent a confidential letter, which leaked, containing proposals for cooperation to assure Syria's reconstruction and the return of refugees.

US President Donald Trump decided in December to withdraw US troops from northeastern Syria, where they had fought alongside Kurdish forces against IS, but he has since agreed to leave behind a residual force of about 200 US troops.

Washington is currently negotiating with Western allies in the anti-IS coalition on an international force that would train security forces capable of stabilizing parts of Syria.

US officials say IS is on the verge of losing its last bit of territory in Syria.