As far as military losses go, "the loss of one aircraft is nothing, but politically it has great significance and far-reaching consequences," Klintsevich said. Other lawmakers are concerned about how the militants could have acquired the anti-aircraft weapon. "We have information that the MANPADS used to bring down our jet was brought into Syria from a neighboring country several days ago," MP Dmitry Sablin, coordinator of the Russia-Syria parliamentary friendship group, told Interfax. "Countries from whose territory weapons arrive, that are then used against Russian servicemen, must understand that whis will not go unpunished," he added.
A Pentagon spokesperson, interviewed by TASS, has already denied the US sent anti-aircraft weapons to Syria. However, the 2017 defense spending bill, signed under Barack Obama, opened the door for the supply of such weapons to Syrian rebels – a fact that Moscow sounded the alarm over when the bill was inked.
However, it envisages careful vetting of the recipients and extensive paperwork, and the Pentagon has previously said that no such deliveries have actually been made.
In mid-January, a report by the Syrian online outlet Al-Masdar claimed Kurdish forces operating in Syria had received a shipment of MANPADS from the US in an "independent secret deal." The report cited unnamed "opposition sources."