MANILA, Oct. 18 (Xinhua) -- Three police officers were killed and three others wounded Thursday in a roadside ambush in Camarines Sur province in the northern Philippines.

Police said the police officers were escorting Food and Drug Administration (FDA) Director General Nela Charade Puno when their convoy was ambushed around 9 a.m. local time in a roadside ambush in a town in Camarines Sur province in the southern Luzon.

Health Secretary Francisco Duque said Puno and her team were on their way to a town named Daet in Camarines Norte province on Thursday morning when their convoy of cars were fired at by unidentified armed men.

Duque said Puno and her team were "unharmed and were brought to a secure location."

"Investigations are currently underway," Duque said, adding he "condemn in no uncertain terms the attack on (Puno)."

Police said rebels may have been behind the attack.