The Al-Nusra Front, al Qaeda’s Syrian affiliate, has asked extremists in the Caucasus to launch an attack against Russian soldiers and nationals. The move is in retaliation for Russia’s involvement with the Syrian government against the Islamic State group.

Al-Nusra head Abu Mohamed al-Jolani said in an audio message released Monday that the extremists should go for "an eye for an eye." If Russia can kill their soldiers and people, they can also kill Russia’s, he said.

"The war in Syria will make the Russians forget the horrors that they found in Afghanistan," AFP quoted al-Jolani as saying. "They will be shattered, with God's permission, on Syria's doorstep."

According to al-Jolani, attacks against the Russian should stop when the Kremlin stops attacking Syrian village and cities.

"I call on all armed factions to gather the highest number of shells and rockets and to hurl hundreds of rockets every day at the Nusayri (derogatory term apostates) for villages, just like the scoundrels do to the Sunni villages and towns, to make you taste what our people are suffering," he said. "Delay the disputes until the demise and smashing of the Western Crusader and Russian campaign on Syrian land."

Russia started its air campaign against ISIS militants in Syria in September. While al-Jolani warned Moscow to expect ominous consequences for its operation in Syria, two shells have reportedly struck the Russian embassy in Damascus Tuesday.

The strike took place when hundreds of people gathered outside the building to extend their support for the Russian airstrikes. Russian Foreign Minister Sergei Lavrov called the attack "a terrorist act" which, according to the BBC, caused widespread panic and smoke coming from the embassy compound.