The first batch of coronavirus vaccines arrived in Singapore on Monday on a flight from Brussels, according to a statement from Deutsche Post AG-owned DHL that didn’t specify which pharmaceutical company made the jabs.

Singapore Prime Minister Lee Hsien Loong said earlier this month that the nation has approved the use of Pfizer Inc. and BioNTech SE’s vaccine and expects the first shipments by the end of December. Advance purchase agreements have also been made with other promising candidates, including those from Moderna Inc. and Sinovac Biotech Ltd., he said.

“The cargo arrived at Singapore’s Changi International Airport on Dec. 21 where DHL handled the customs clearance and final delivery to a designated location in Singapore,” the logistics company said. DHL will also “handle the return of these special shipper boxes to Europe.”

Temperature trackers equipped with GPS were packed within each thermal shipping box to provide visibility throughout the vaccine’s journey, according to DHL’s statement.

Singapore-based ground handling operator SATS Ltd. has increased daily production of dry ice to around 4.5 tons in anticipation of the vaccines, which must be stored at ultra-low temperatures.

To provide global coverage over the next two years, DHL has estimated that about 15 million cooling boxes will be required across various supply chains.

Singapore has set aside more than S$1 billion ($750 million) for vaccines and should have enough for its around 5.5 million-strong population by the third quarter.