An explosive device killed one Russian soldier and wounded three others during a patrol in northern Syria, the Russian Ministry of Defence said in a statement.
The three wounded soldiers have been hospitalised and are in a stable condition, news reports said.
"On June 9, during a patrol by the Russian military police in the province of Hassakeh in the Syrian Arab Republic, an armored car was hit in the explosion of an unidentified device," the ministry statament said.
"One Russian serviceman died as a result of the explosion," it added.
In 2015, Russia joined the Syrian civil war to help President Bashar Al-Assad regain control of large areas of the country which had fallen into the hands of opposition groups. It is credited with helping ensure Al-Assad's survival.
Last year, Moscow announced that it is expanding its naval base at the Syrian port of Tartus and planning to construct a floating dock to boost the port's ship repair facilities.
Russia says it has lost 112 military personnel in Syria, however it is widely believed that Moscow hired private mercenaries to support its actions in the war.