MOSCOW (Reuters) - Militants in Afghanistan who have switched sides to Islamic State pose a growing risk to Central Asia, Alexander Bortnikov, the head of Russia's Federal Security Service, was quoted as saying by the RIA news agency on Wednesday.
Kremlin officials view the ex-Soviet republics of Central Asia as a last line of defense stopping Islamist militants reaching Russia itself, and say they worry the region's fragile security forces may not hold up without help.
"The escalation of tension in Afghanistan is a source of serious concern," the news agency quoted Bortnikov as saying. "Numerous militant groups that are part of the Taliban are concentrated on the northern borders of that country."
"Some of them have taken up the banner of Islamic State, which has led to a sharp increase in the threat of terrorists infiltrating Central Asia," Bortnikov said.
The Kremlin cited the threat from Islamic State as the reason for its military intervention in Syria, though Western governments accused Russia of getting involved to prop up its ally, Syrian President Bashar al-Assad.
Russia's heightened attention to Central Asia -- a region that for centuries has been the subject of geo-political rivalry between great powers -- coincides with a renewed interest in the area in the United States.
U.S. Secretary of State John Kerry will, starting late this week, travel to all five central Asian republics, the State Department said in a statement.
He will use the visits to Kyrgyzstan, Uzbekistan, Kazakhstan, Tajikistan and Turkmenistan to meet senior government leaders and to discuss regional issues, the statement said.
Reporting by Katya Golubkova and Christian Lowe; Editing by Andrew Osborn