MANILA, Philippines -- Security measures in the cities of Caloocan, Malabon, Navotas and Valenzuela (Camanava) have been intensified following intelligence reports that two top leaders of the Communist Party of the Philippines (CPP) were sighted in Valenzuela City, a police official said on Friday.

Chief Superintendent Pedro Tango, director of the Northern Police District, told the Philippine Daily Inquirer they received information that Ramon Ferdinez and Leody de Guzman, both members of the central committee of the CPP, were seen in several areas of the city.

“We are still validating the report of their presence in our area, but measures are already in place to prevent them from exploiting present issues,'' said Tango.

Tango was referring to the arrest of CPP founder Jose Ma. Sison in The Netherlands and the conviction of former president Joseph Estrada for plunder on Wednesday.

“All precincts and operating units were already on the lookout for known communist leaders and their activities,'' the NPD chief said.

He explained that intelligence gathering, particularly in the villages are being conducted as a precautionary measure to secure police precincts.

Tango said that police are also confirming reports of plots to attack PNP stations, government buildings and assassinate police and military personnel as part of their retaliation on the arrest of Sison, who was released on Friday by the Dutch government for lack of evidence.