TOKYO (AP) — Japanese Prime Minister Yoshihide Suga asked the U.S. drug maker Pfizer Inc. for additional supplies of the COVID-19 vaccine to speed up the inoculation drive that lags behind many other countries.

Suga, after holding talks with President Joe Biden at the White House, wrapped up his Washington visit on Saturday with a phone call to Pfizer CEO Albert Bourla.

Suga requested Burla for additional supplies of the vaccine that would cover all eligible recipients by September, as well as to ensure the stable and prompt delivery of the ongoing vaccine shipments, Japanese officials said Sunday. No details were released.

According to the officials, Burla told Suga that Pfizer planned to closely coordinate with the Japanese government to discuss the requests.

Japan, with its domestic vaccine development still in early stages, has to rely on imports and has signed agreements with Pfizer, AstraZeneca and Moderna. The Pfizer vaccine is the only one Japan has approved so far.

Japan’s government says it has secured 314 million doses, enough to cover its entire population by the end of this year. That includes 144 million doses from Pfizer.

Inoculations started in mid-February and have covered less than 1% of the population. The slow process is hampered by the shortage of vaccines amid export controls by the European Union.

A recent surge in cases led the government to issue an alert status for Tokyo and nine other urban prefectures. It has also fueled doubts about whether or how the July 23-Aug. 8 Tokyo Olympics can go ahead.

Japan added 4,532 cases on Saturday for a total of 525,218 since the pandemic began, with 9,584 deaths.