Beijing: Terrorists currently fighting in Syria may sneak into Russia disguised as immigrants to unfold sabotage, the Federal Security Service (FSB) said on Thursday.
"We expect that amidst armed conflict in Syria the armed fighters and terrorists could infiltrate into our country inside the illegal immigrants flows," head of FSB counter-intelligence analytical department Alexander Roshchupkin told a hearing in the Federation Council, or upper house of Parliament.
He said the FSB is monitoring this security threat.
According to Roshchupkin, the FSB is aware that some groups of illegal immigrants arrived in Russia for subversive and intelligence activities.
He said Russian security service has uncovered several professional spies working in the North Caucasus.
"Illegal immigration is one of the tools to destabilise situation in Russia," Roshchupkin said, adding that formation of isolated immigrant communities creates security threats for Russia.
The illegal industry of immigrants` transit to Europe via Russian territory has been actively working, he noted.
The FSB pointed at unpoliced borders between Russia and CIS countries as well as at omissions in Russian law which facilitates criminal groups to conduct such activity.
"No one can say how many immigrants have arrived and how many have left, even in the border service," the officer said, describing the situation as grave.
The Federal Migration Service (FMS) estimates the number of illegal immigrants at 3.3 million.
"Today over 10 million foreign nationals have been to Russia, 8 million out of that number are citizens of the CIS countries, 3.3 million out of them violate migration law," FMS deputy head Anatoli Fomenko said during the same hearing.
Earlier this month, FMS chief Konstantin Romodanovsky vowed to tighten control over immigrant flows and said the authorities planned a massive crackdown on illegal immigrants later this year.
Also in May, Prime Minister Dmitry Medvedev said Russia would create a system to monitor and control the flow of migrant workers to secure social stability.