A Russian intelligence official warned Wednesday that large numbers of Islamist fighters belonging to the Islamic State group and Taliban are amassing on Afghanistan's northern border and could be preparing to invade Central Asia.

Russian Federal Security Service Director Alexander Bortnikov made the announcement during a security meeting with special services from the Commonwealth of Independent States, according to The Associated Press.

"The international community has now hit a new geopolitical challenge, an international criminal group in the name of the Islamic State. This project, which grew out of the 'Arab Spring,' has gained momentum thanks to the double [political] standards of certain world regional powers by using 'a terrorist battering ram' to reach their own strategic goals in Asia and Africa," Bortnikov said, according to Sputnik News.

"According to our estimates, citizens from more than 100 countries are currently fighting in the ranks of terrorists structures and the recruits constitute up to 40 percent of their forces."

He added that the risk of invasion has grown as some Taliban fighters are now fighting on behalf of the Islamic State group.

"The escalation in tensions in Afghanistan has brought on serious dangers. There are numerous criminal groups included in the Taliban movement on the northern borders of this country right now. Some of them have also [began operating] under the Islamic State flag, which has led to a sharp rise in the threat of terrorists invading Central Asia," Bortnikov said.

Afghanistan shares a porous border with countries like Turkmenistan, Uzbekistan and Tajikistan, all former Soviet republics.

At the request of Syrian President Bashar al-Assad, Russia began conducting airstrikes against the Islamic State group as well as separate U.S.-backed rebels in Syria on Sept. 30.

Some speculate that the extremist fighters could now be trying to open up a new front to the north of its established territories in Syria and Iraq in an attempt to force Russia to expand its combat mission across a larger swath of territory. They may also be able to gain control of lucrative drug trafficking routes, where raw opium flows from Afghanistan to the streets of Russian and Europe, according to the Express.

Earlier this month, Russian President Vladimir Putin called the situation in Afghanistan "close to critical" and asked the other ex-Soviet countries to be prepared to work together to counter an attack, reported AP.