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 militants have a presence, police said, according to AP. 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. It was not immediately clear why the police made public the terror alert upgrade only now. The U.S. and a few other Western governments have warned their citizens not to travel in Mindanao areas due to the possibility of terror attacks. Police foiled an attempted bombing of the annual national games attended by hundreds of local athletes last month in southern Koronadal city when they found two homemade bombs intended to be exploded by Muslim militants during the closing ceremony, police said. -- SPA