Mendoza also warned politicians against using private armies to gain leverage against their opponents in the May congressional and local elections.
"We are monitoring all these critical spots," he said. "The PNP is working for the peaceful conduct of the elections."
Mendoza said election hot spots may be classified into "areas of concern" and "critical areas." Fifty-two provinces are considered areas of concern, while 309 places are critical areas.
Mendoza said most areas classified as critical are in Mindanao, where local elections have often been marred by violence as politicians subscribe to the use of the so-called "Three Gs"  guns, goons and gold.
Mendoza said elections in Metro Manila and Southern Tagalog are expected to be peaceful even as he ordered National Capital Region police chief Deputy Director General Romeo Peña to intensfiy police surveillance operations in the metropolis. – Christina Mendez