"One of major terror acts was averted in the Moscow region several days ago," FSB chief Alexander Bortnikov told the Kremlin chief.
He said in televised remarks the agency had detained four people from the restive Northern Caucasus, adding the militants had planned to target public places and "transport infrastructure" in the Moscow region.
The FSB also confiscated several explosive devices carrying 10 kilogrammes (22 pounds) of TNT equivalent, arms and maps, Bortnikov told Medvedev.
Russia is battling a Muslim insurgency in the North Caucasus where attacks on officials are a daily occurrence and after a lull of several years, suicide attacks have returned to Moscow.
A suicide bomber from the North Caucasus killed 37 people at Russia`s busiest airport Domodedovo in January. Two female suicide bombers from that region killed 40 and wounded dozens on the underground during morning rush hour last year.
Over the past six months Russia has seen 169 terror-linked crimes including 110 in the Caspean region of Dagestan which has experienced most of the deadly violence, Bortnikov said.
The FSB national security service has lost 95 employees over the same period, while 200 have been wounded, he added.
The Kremlin calls the Caucasus unrest its biggest domestic problem. Russia`s leading Islamist rebel Doku Umarov in February vowed to make 2011 "a year of blood and tears," urging the Kremlin to withdraw from the region.
The Russian authorities have repeatedly said that letting the Caucasus go and negotiating with "terrorists" was not an option. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
