MANILA (UPDATE) - Experimental COVID-19 vaccines used by President Rodrigo Duterte's security group were smuggled, Defense Secretary Delfin Lorenzana said Wednesday, as authorities are investigating how it got past border inspection.

"Yes, it’s smuggled. Kasi hindi authorized na pumasok dito (Because it was not authorized to enter here). Only the government can authorize that through the FDA (Food and Drug Administration),” he told reporters during the Rizal Day celebrations in Manila.

While the use of vaccines was unauthorized, Lorenzana believed the early inoculation of members of Presidential Security Group (PSG) was "justified".

"Explain lang talaga ng PSG kung bakit nila ginawa 'yon. Justified naman eh. Anyway 'yong vaccine naman ay hindi fake. Totoo naman," he said.

(The PSG should explain why they did it. It's still justified. Anyway, the vaccine was not fake. It's real.)

The defense chief is not aware who donated the vaccines, which were reportedly developed by Chinese drug maker Sinopharm.

Lorenza revealed he had received rumors before of such vaccination but didn't inquire further.

"Basta alam namin noon, ang rumors na kumakalat ay nagpabakuna na 'yong PSG. Who authorized it, hindi naman kami nagtanong," he said.

(There were rumors before that members of PSG had been vaccinated. We didn't ask who authorized it.)

"Ngayon pa lang lumalabas 'yong facts na 'yan ay hindi pa pala authorized na vaccine sa Pilipinas," he added.

(It was only revealed now that the vaccine is not authorized for use in the Philippines.)

Although he administratively oversees the Armed Forces of the Philippines (AFP), he cannot impose sanctions to PSG because it is a detached unit from the military force.

Moving forward, Lorenzana said he would no longer allow the military to accept unauthorized vaccines from here on.

"Mga sundalo natin? Huwag muna. Kailangan sundin natin 'yong procedure. Kaya nga tinatag natin 'yong FDA eh para meron tayong procedure diyan," he said.

(Our soldiers [getting vaccinations]? Not for now. We should follow the procedure. That's why there's an FDA because we have procedures to follow.)

For his part, PSG chief Jesus Durante said the vaccinations began in September and the last batch was in October.

"It started actually September and the last batch October...All of the personnel inoculated so far are doing good. No side effects whatsoever," he said in an ANC interview.

He also said the President was not informed about the inoculations until after the PSG men were vaccinated.

"We didn’t ask permission. We just informed him about it after all the close-in personnel were vaccinated. He was surprised," he added.

• Presidential Security Group got coronavirus vaccines in September, says chief

In light of the incident, the Bureau of Customs (BOC) is investigating the possible smuggling of the vaccines.

"Based on our records, wala pong nag-declare sa amin ng vaccines (no one has declared vaccines)," BOC assistant commissioner and spokesperson Vincent Philip Maronilla told Teleradyo.

The Customs official suspect the vaccines passed through the airport because it requires cold storage.

Even if the vaccines were donated as earlier claimed by Malacañang, Maronilla said it would still require approval from regulatory agencies.

"'Pag donated po kasi and it's still, let say for example vaccine, this will still have to go through some licensing, some sort of permit coming from the FDA before it can be released. At least kung walang permit, we usually allow the FDA to tell us if it’s okay for products to be released," he said.

It was President Rodrigo Duterte who revealed in his public address on Saturday that some soldiers had already been vaccinated against COVID-19.

Military officials confirmed the move to the dismay of health-care workers, who should be the first to get inoculated against the raging virus.

• Palace: COVID-19 vaccine given to PSG was 'a donation'

The Palace had said the vaccines used by PSG were donated and maintained it found nothing illegal in the inoculation, saying it was meant to protect the President from risk of COVID-19 infection.

• Unauthorized use of COVID-19 vaccine illegal, FDA says after Duterte's PSG inoculated

However, the FDA maintained that unauthorized use of COVID-19 vaccine is illegal.

“As of date, the FDA has not issued any emergency use authorization (EUA) to any vaccine for COVID-19. Without the proper authorization, there is no guarantee on the safety, quality and efficacy of said vaccine as the same has not undergone the required technical evaluation by the FDA," FDA director general Eric Domingo had said.

The agency said "manufacture, importation, exportation, sale, offering for sale, distribution, transfer, non-consumer use, promotion, advertisement, or sponsorship of any unauthorized vaccine" remain prohibited.

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- With a report from Chiara Zambrano, ABS-CBN News