Philippine security officials raised the terror alert to the highest level in two southern regions, including one where authorities foiled a bomb attack on a national athletic event, due to the threat of bombings, police said Sunday. The terror alert was raised from "high" to "critical" - the highest in a four-level alert system - for the month of May in the mountainous heartland of southern Mindanao island and a nearby Muslim autonomous region where al-Qaida-linked operatives have a presence, police said. Terrorist threats "have breached the critical level" in the two regions, according to a police statement. A critical alert means a terror attack has occurred or has just been foiled and follow-up attacks could be carried out. "Both have happened in those areas," police Chief Superintendent Samuel Pagdilao said.