MANILA (Updated) -- The Philippine National Police (PNP) Maritime Group has confirmed issuing a memorandum to the operations managers of shipping lines warning of possible entry of seven vehicles carrying explosives at seaports.

Maritime Group director Chief Superintendent Marcelo Morales said the memorandum issued by its station in Zamboanga del Norte to shipping lines in Mindanao was legitimate but the information was unverified.

The memorandum dated June 2 said two sedans and four sports utility vehicles known to be carrying improvised explosive devices are on their way to roll-on, roll-off and port terminals.

The document, which circulated online last weekend, was signed by Senior Police Officer 4 Allan Pestañas of the 904th Maritime Group based in Zamboanga del Norte.

The memorandum listed the following vehicles:

Black Toyota Hilux (license plate TO 4823)

White Nissan Sentra (license plate UER 452)

Black Toyota Land Cruiser (license plate VIM 889)

Black Honda Civic (license plate KDY 462)

Gray Toyota Vios (license plate ZBM 340)

Black Isuzu D-max (license plate PIJ 139)

Black Toyota Innova (license plate ZDT 395)

"'Yung nilalaman na 'yun mga plate numbers na 'yun ay parang nadinig lang n'ya (Pestañas) sa iba't-ibang tao and ginather niya and gumawa siya ng listahan at shinare doon sa mga operations manager ng shipping lines kasi regular ‘yung meeting nila doon. Part ng enhanced security measures is 'yung information sharing," Morales said.

Morales urged the owners of the vehicles to go to the nearest police station and clear their names. He said they are not placing the said vehicles on red flag order as verification is still ongoing.

"Kung talagang sa kanila 'yung vehicles na iyon pwede naman silang pumunta and voluntarily makipag-usap sa police station natin especially sa maritime police station," he said.

He said they will also not prevent the owners of the vehicles to press charges against those who issued the memorandum.

Morales said he had already talked to Pestañas and reminded him to be careful in disseminating confidential information outside of PNP.

The memorandum was issued amid the ongoing gunbattle between government troops and the Maute terror group in Marawi City, which prompted President Rodrigo Duterte to place the entire Mindanao under martial law.

Police are now investigating who among their men leaked the document.

PNP spokesperson Dionardo Carlos warned the public against sharing sensitive information online.

"We appeal to the public that if there are such information particularly concerning the security or terrorism, do not pass it around. The best is to immediately inform the authorities para ma-check," he said. (SunStar Philippines)