The Philippine National Police (PNP) went on full alert over the weekend for the 5th anniversary of the Sept. 11 terror attacks in New York and the Pentagon in the United States, Manila media reported on Monday.
In Metro Manila, vital installations were put on red alert against terrorist threats. Elsewhere, security forces likewise heightened their alerts, according to a report by ANC TV.
At the Metro Rail Transit and Light Rail Transit stations, police and security guards continued to enforce the ban on liquid substances, the report said.
The red alert was also raised in the country's air and sea ports.
The PNP alert coincided with the departure of Philippine President Gloria Macapagal-Arroyo on Saturday for a five-nation tour of Europe, Cuba and Hawaii in the U.S.
More than 2,000 people died and thounsands more were injured after suicide bombers of the al Qaeda network hijacked and crashed passenger jets onto the World Trade Center and the Pentagon five years ago.