A senior Russian intelligence official has warned of the potential influence of the Islamic State group inside Russia.

Gen. Sergei Smirnov, deputy chief of the FSB intelligence agency, was quoted by Russian wires on Friday as saying that the group is "beginning to infiltrate" terrorist organizations focused on operating inside Russia's predominantly Muslim North Caucasus.

Russian federal forces have fought two separatist wars in Chechnya, which has become more stable under the watch of Kremlin-backed strongman Ramzan Kadyrov. The Islamist insurgency has since spread to other North Caucasus provinces where bombings and killings of law enforcement officers have become almost a mundane occurrence.

Smirnov says intelligence agencies estimate that about 1,700 Russian nationals have gone to join the Islamic State group to fight in Syria and Iraq.