Russian security officers work at the site of an explosion near a bus stop at Michurinsky Avenue in Moscow, capital of Russia, Moscow March 9, 2011. (Xinhua/Lu Jinbo)

MOSCOW, Dec. 9 (Xinhua) -- Three armed suspects were killed Saturday in Russia's North Caucasus city of Stavropol for allegedly planning terrorist attacks in public places, Sputnik news agency reported, citing a Federal Security Service statement.

Law enforcement authorities launched an operation early Saturday, foiling terrorist attack attempts of a group of gunmen, according to the statement. Several streets were under lockdown during the operation.

The North Caucasus region is a hotbed of insurgency, with separatists and extremists frequently attacking governmental, military and police facilities as well as civilians.