MANILA - Six suspected hijackers were killed in separate encounters with police in the northern Philippine province of Cavite early Friday.

Local media abs-cbnnews.com reported that policemen spotted four of the suspected hijackers in the village of San Agustin in the city of Dasmarinas. Three were on board a plateless Mitsubishi Adventure while one suspect drove an Isuzu van filled with sandwich spread.

Police said they tried to flag down the suspects but they immediately fired shots.

The four suspects were killed after police chased them. Two of the suspects, identified as Jonjie Lianco and Robert Santos were in police uniform. The other fatality was identified as Jesse Gonzales Villanueva.

Police have yet to identify the fourth suspect but they said a gun with the seal of the Philippine National Police (PNP) was recovered from him.

Cavite Police director Senior Superintendent John Bulalacao said they have yet to find out whether the slain suspects were part of the PNP.

Meanwhile, in a follow-up operation, two more suspected hijackers were killed in a warehouse in the village of Langkaan 2 in Dasmarinas.

The identity of the two slain suspects was not immediately known. Bulalacao said it is possible that the six slain suspects belong to a single group.

According to Cavite police, four incidents of hijacking in the province have been recorded in the past two months.