Manila  - The Philippines on Wednesday mounted search and rescue operations for a missing air force helicopter carrying senior staff of President Gloria Macapagal Arroyo amid reports that the chopper could have crashed and exploded.

The Bell 412 helicopter, carrying five passengers and two pilots, was on its way to Banaue town in Ifugao province, 270 kilometres north of Manila, from the nearby mountain resort city of Baguio when it went missing Tuesday.

Brigadier General Horacio Lapinid, an air force commander, said police, air force and military rescue teams have been dispatched to the area between Baguio and Banaue to look for the missing helicopter.

The United States also dispatched two helicopters, which are in the Philippines for joint military exercises, to help in the search.

"So far our search is still negative," Lapinid said. "We have at least six helicopters involved in the search."

Lopez Tugong, mayor of Tingoc town in Ifugao, said local residents reported to police that they heard an explosion at the same time the helicopter was supposed to have gone missing.

"According to residents, the helicopter crashed and exploded in an area in Tingoc," Tugong told a Manila radio station. "I have directed police to go to the area and verify the report."

The chopper's passengers were Press Undersecretary Jose Capadocia, Appointments Undersecretary Malou Frostrom, Air Force Brigadier General Carlo Clet, a senior military aide Arroyo, an assistant secretary of the Presidential Management Staff and Clet's aide.

The officials were on their way to Banaue as an advance team for a scheduled visit of Arroyo on Wednesday. The trip was cancelled and senior aides said the president was "shaken" by the news of the missing chopper. (dpa)