Russian authorities said on Tuesday they had prevented a series of suicide attacks on the capital last month, underscoring analysts' fears a simmering insurgency in the country's south could reach Moscow, Reuters reported. "According to documents from law enforcement services, the activities of five militants trained for suicide attacks were prevented," Alexander 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 Sept. 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 neighbouring Ingushetia and Dagestan, have shattered a few years of relative calm in the North Caucasus.