MANILA - President Rodrigo Duterte on Monday night reiterated the need for a vaccine for the Philippines to overcome the COVID-19 pandemic, even as he said the potential vaccine from China or Russia will not be for free.

"As I have stated, time and again, repeatedly, the only salvation available to humankind at this time of life, if you are stricken with the virus, the answer is always vaccine," Duterte said in a televised public address late Monday.

Duterte also thanked Russia and China anew for expressing their willingness to supply the Philippines with vaccines once these become available.

"I would like to thank Russia, President Putin, and China, President Xi Jinping, for offering to provide us with the vaccine as soon as it is possible for distribution to the public," he said.

"I cannot overemphasize my debt of gratitude. But remember that this is not for free, for after all , they did not develop the vaccine without great expense, and also the human effort involved," Duterte added.

Duterte said the Philippines will pay for the vaccines, but he'll ask China and Russia for a credit line if the vaccines are too expensive.

"Bibilhin natin 'yan, kaya lang kung mahal, if it is quite expensive, then I will ask my friend, President Putin and President Xi Jinping to give us a credit. Parang utang, credit line, but we will pay, not in one payment but by installments," he said.

"Basta ang sinasabi ko, magbayad tayo. Hindi ito libre. At I will always tell them, we are willing, and if we are short of money by this time, because all of the economy of the world, individual countries, have fallen flat. Lahat ngayon nagkakaroon ng economic hemorrhage," Duterte added.

The Russian government earlier green-lighted its Sputnik V vaccine, claiming to be the world's first against the new coronavirus.

President Vladimir Putin said the vaccine "passed all the needed checks," and that his daughter was among those inoculated.

But the speed with which the vaccine got regulatory approval had experts worried that Russia skipped important steps in vaccine development for the sake of global acclaim.

• WHO wants to review Russian vaccine safety data

The Russian vaccine was issued a certificate of registration despite a trial reportedly involving only 76 people, according to an article in sciencemag.org and other news reports. It's among 165 candidate vaccines listed by the WHO as of July 31, and was still in an early phase of development.

In his public address last week, Duterte confirmed willingness to participate in the Russian immunization program.

The 75-year-old President even volunteered to be among the first to be injected with the Russian vaccine in public to prove its safety and efficacy.

• 'In public, magpa-injection ako': Duterte thanks Russia for coronavirus vaccine offer

Malacañang said the Philippines and Russia are planning to start phase 3 clinical trials of Moscow's coronavirus vaccine by October, raising hopes on a solution to the pandemic that has infected over 20 million people worldwide.

• PH, Russia to run simultaneous phase 3 clinical trials for COVID-19 vaccine