MOSCOW (Reuters) -- Russian authorities said they had prevented a series of suicide attacks on the capital last month, underscoring analysts' fears a simmering Islamist insurgency in the country's south could reach Moscow.
"According to documents from law enforcement services, the activities of five militants trained for suicide attacks were prevented," Aleksandr Bortnikov, the head of the FSB, the successor to the KGB, told Russian media.
Referring to one man who was detained in Moscow, Bortnikov said he was planning a "terrorist attack" during a public holiday on September 5, when tens of thousands of Muscovites strolled car-free streets in the heart of the city near the Kremlin.
An investigation has been launched into the five men's activities, the head of the security services added.
A series of suicide bombs and armed attacks on police and security forces in Chechnya, where Russia has fought two separatist wars, and neighboring Ingushetia and Daghestan, have shattered a few years of relative calm in the North Caucasus.
Fears among officials and analysts have grown in recent weeks that the violence along Russia's south -- a major headache for the Kremlin -- could spill over into other parts of Russia.
"As long as the problem in the North Caucasus is unresolved, there will always be a risk for Moscow," said Sergei Goncharov, head of a group of former elite KGB troops and a deputy in the Moscow city government.
"For every three they catch there are another two planning a similar attack," he told Reuters by telephone.
Late last month gunmen killed a senior official from Daghestan in Moscow, in the first of such attacks on the capital in recent years.
The Kremlin, which lifted decade-long tight security restrictions in Chechnya in April, has refrained from reintroducing such measures in the North Caucasus.
But local leaders have warned Russian President Dmitry Medvedev that an Islamist uprising has permeated all spheres of society in the region and that they are struggling to contain it.