On June 18, a US Navy fighter jet downed a Syrian government warplane — the first such incident between the United States and Syria in more than six years of war in the country. The Pentagon said the Syrian jet had attacked US-supported Syrian Democratic Forces (SDF) fighters near the north-central Syrian town of Ja’din. Syria had a different narrative, saying the plane was downed “in the Raqqa countryside” while Damascus “was carrying out a military operation” against the Islamic State (IS), thus condemning the US attack as an affirmation of its “real stance in support for terrorism.”

The Syrian narrative was almost immediately picked up by Russia. However, the tone of Moscow’s statements was different. The initial response of Russian Foreign Minister Sergey Lavrov — who is in China for the meeting of BRICS (Brazil, Russia, India, China and South Africa) foreign ministers — was rather measured. On June 19, Lavrov reiterated the necessity to fully respect Syria’s sovereignty and territorial integrity and called on the United States and “all others who have their forces or their advisers” in Syria to coordinate their efforts. He also emphasized that actions should be coordinated with Damascus.

Russia’s Defense Ministry was much tougher in its response. It first slammed the US attack as “cynical” and said it could be considered “an act of aggression.” What seemed particularly disappointing for the Russian side, according to the statement, was that “the command of the coalition forces did not use the existing channels of communication between the command of al-Udeid air base (Qatar) and the Khmeimin air base command to prevent air incidents in the airspace of Syria” — an important point from Moscow’s perspective, since Russian forces were also performing combat missions in Syrian airspace at the time.

The Russian Defense Ministry interpreted the US action “as an intentional failure to fulfill its obligations” under a 2015 memorandum about preventing such incidents and decided “to stop the cooperation with the American party within the memorandum.” The ministry demanded a thorough investigation and accounting from the US command.