Sri Lanka's army also set up a new brigade in Kinniya near the eastern port of Trincomalee, where thousands of angry people last week besieged a government office after fighting with the navy in pursuit of suspected "grease devil." The increased deployment came a day after a mob killed a police officer in the northwestern town of Puttalam.

Troops have remained out in force since Sri Lanka's government won a 25-year civil war in May 2009 with the Tamil Tiger ethnic separatists. "The military and the police are doing the patrols in the towns and the areas affected by the incidents in the east, northwest and north," military spokesman Brigadier Nihal Hapuarachchi said.

More than 30 incidents of violence and vigilantism have been reported in eight districts of the country, primarily in areas inhabited by minority Muslim or Tamil people as the government and opposition trade blame over the phenomenon.