US President Joe Biden, at his first summit with President Moon Jae-in earlier this month, promised to supply shots for 550,000 South Korean troops. The two agreed to forge a vaccine partnership to boost regional and global supplies.

Kim said the shipment of the J&J vaccines had doubled since the summit and will arrive this week, thanking the Biden administration for showing its commitment to the bilateral alliance.

"We plan to administer the vaccines on military-related personnel, including reserve forces and the civil defense corps, after airlifting them directly from the United States using military planes," Kim told an intra-agency meeting.

Around 10 million Americans, including soldiers, have received J&J shots and the incoming doses will be immediately usable upon arrival, he said.

The US Forces Korea had offered to give 13,000 doses of the vaccine ahead of the summit.

Global shortages and shipment delays have posed uncertainties in South Korea's vaccine rollout, deepening public skepticism over its goal of reaching herd immunity by November.

South Korea's food and drug safety ministry granted final approval for the J&J product in April, after signing a deal to import the vaccine for 6 million people, though the date for their shipment has not been finalized.

As of Saturday, around 5.4 million out of the country's 52 million population have received at least a first dose since the inoculation drive began at the end of February, according to the Korea Disease Control and Prevention Agency.

Meanwhile, Taiwan has not given up hope of eventually getting COVID-19 vaccines from Germany's BioNTech SE, Health Minister Chen Shih-chung said on Sunday, a deal that Taipei's government has blamed China for not being able to complete.

After recording just a handful of daily infections for months, Taiwan is dealing with relatively large numbers of community transmissions, though infection rates are starting to fall.

It has only vaccinated around 1 percent of its more than 23 million people but has almost 30 million shots on order, from AstraZeneca Plc, Moderna Inc and two domestic firms.

The Chinese-claimed island has blamed Beijing for nixing a deal earlier this year for BioNTech vaccines, which China denies.

Chen told reporters that although talks for that shot had "somewhat hit the rocks", Taiwan "has not completely given up hope" of obtaining them.

Shanghai Fosun Pharmaceutical Group Co has a contract with BioNTech to sell the vaccines in Greater China, including to Taiwan, but Taiwan's government says it will only deal with Germany's BioNTech directly and does not trust vaccines from China.

Outside of Greater China, BioNTech has partnered with Pfizer Inc.

Chen said that in late January, the COVAX vaccine-sharing scheme for lower-income countries had told Taiwan it could get shots from Pfizer, but on May 3 COVAX informed the government that would not be possible.

Taiwan is under its second-highest level of curbs to stop the spread of infections, including limiting personal gatherings and closing entertainment venues.

Chen said the task was to ensure those measures were being properly enforced, adding, "At present there are no plans or intentions for a lockdown."

The government has come under fire from opposition parties for delays in testing and reporting positive cases, but Chen said that was now improving.

Taiwan reported 355 domestic COVID-19 cases on Sunday, down from 486 on Saturday. Total daily cases peaked on May 17 and have been falling since Friday.

Taiwan has reported 8,160 infections since the pandemic began, including 110 deaths.