HANOI - Vietnam is in talks with the United States on domestic production of mRNA vaccines, its foreign ministry said on Thursday, as the Southeast Asian nation looks to boost supplies amid its worst coronavirus outbreak yet.

After reining in the virus for much of the pandemic, Vietnam faces a surge in daily infections, forcing strict curbs on movement in about a third of the nation, including its commercial hub of Ho Chi Minh City and the capital, Hanoi.

Local production of the unidentified mRNA vaccine could begin in the fourth quarter or early in 2022, foreign ministry spokeswoman Le Thi Thu Hang told a regular news briefing.

Vietnam could produce 100 million to 200 million vaccine doses a year under such a deal, she added.

U.S. drug firms Pfizer and Moderna, which use new messenger RNA (mRNA) technology in their vaccines, did not immediately reply to Reuters' requests for comments.

Such vaccines contain no actual virus, instead providing instructions for human cells to make proteins that mimic part of the coronavirus. These instructions spur the immune system into action, turning the body into a virus-zapping vaccine factory.

Many Asian governments are looking to build up vaccine production at home as tight global supplies have hobbled their inoculation campaigns, which lag North America and Europe in the battle against a surge in daily infections.

BioNTech has a production deal with China through local partner Fosun Pharma and plans to build a vaccine factory in Singapore that will begin operation in 2023. 

In South Korea, Samsung BioLogics plans to start vaccine bottling and packaging work for Moderna in the third quarter and the country is in talks with mRNA vaccine makers to make up to 1 billion doses. 

Vietnam will receive an additional 3 million shots of Moderna's COVID-19 vaccine on July 25 from the United States via the global COVAX vaccine scheme, Hang said, adding to the 2 million Moderna doses the U.S. shipped it on July 10.

Hanoi is keen to boost its vaccine capacity.

In May, the World Health Organization said it was reviewing a proposal by an unidentified manufacturer in Vietnam to become an mRNA-based COVID-19 vaccine technology hub.

On Wednesday, Russia's RDIF fund and Vietnamese firm Vabiotech said the latter had produced the first test batch of COVID-19 Sputnik V vaccine and was about to ship it to Russia for quality control checks.

Hang said on Thursday Vabiotech would initially start packaging five million Sputnik V doses a month, using materials from Russia, and moving to produce 100 million doses a year later.

"Vabiotech is also in talks with a Japanese partner to soon transfer vaccine production technologies to Vietnam," she added.

Vietnam's latest outbreak, which includes the highly infectious Delta variant, has accounted for about 95% of its 67,422 pandemic infections and 335 deaths since late April.

The country, with a population of 98 million, has clinched deals for 105 million vaccine doses and is in talks for 70 million more. Fewer than 330,000 people have been fully vaccinated. 

(Additional reporting by Miyoung Kim in Singapore; Editing by James Pearson and Clarence Fernandez)