Taipei, June 20 (CNA) Taiwan on Sunday received a shipment of 2.5 million doses of Moderna vaccine donated by the United States government, obtaining its single largest batch of COVID-19 vaccines in a single day since the pandemic began early last year.

The shipment arrived at Taoyuan International Airport around 4:30 p.m. on a China Airlines cargo flight that had left the Memphis early Saturday, U.S. time.

Shortly after the flight landed, the vaccines were transported to a cold chain logistics center, where they will be inspected by health authorities before being cleared for distribution in Taiwan, according to the Central Epidemic Command Center (CECC).

The donation of 2.5 million Moderna doses comprises 750,000 pledged by the U.S. on June 6 and 1.75 million it added this weekend.

Health Minister Chen Shih-chung , who was at the airport when the shipment arrived, said Taiwan greatly appreciated the donation by the U.S.

At a CECC news briefing earlier in the day, Chen said the large donation by the U.S. was timely, as Taiwan has been battling a domestic outbreak of COVID-19 over the past month.

Taiwan and the U.S. will continue to cooperate in the fight against COVID-19, on the basis of a bilateral memorandum of understanding they signed last year, said Chen, who heads the CECC.

Meanwhile, the American Institute in Taiwan (AIT) Director Brent Christensen was also at the airport to welcome the vaccines.

AIT is the de facto American embassy in the absence of official ties. AIT said Sunday in a Facebook post that "this donation reflects our commitment to Taiwan as a trusted friend and an important security partner."

Taiwan has signed contracts to purchase nearly 20 million COVID-19 vaccines from abroad, including 5.05 million doses of Moderna, 10 million of AstraZeneca, and 4.76 million doses of unspecified brands through the COVAX program.

It has also signed contracts to buy 10 million doses of vaccines from two Taiwanese companies.

To date, however, Taiwan has received fewer than 5 million doses of COVID-19 vaccines, even with the latest shipment from the U.S. and a recent donation of 1.24 million doses of AstraZeneca from Japan.

According to experts, Taiwan will need to vaccinate at least 60 percent of its population to achieve herd immunity and safely reopen to the outside world, which means acquiring around 30 million doses of COVID-19 vaccines.

So far, only 6 percent of Taiwan's 23 million population has received least one COVID-19 vaccine shot.