President Joe Biden has challenged the US to administer 200 million COVID vaccination doses by the end of his first 100 days in office.
That is double the target of 100 million jabs he set in December and achieved earlier this month before his 60th day in office - an average of 2.5 million doses a day.
"I believe we can do it," Mr Biden told reporters at the White House in his first news conference as US president.
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"There are still too many Americans out of work, too many families hurting and still a lot of work to do.
"But I can say to the American people: Help is here and hope is on the way."
The goal amounts to a continuation of the country's existing pace of vaccinations through to the end of month.
Over the next month, the US supply of vaccines is on track to increase and states are lifting eligibility requirements for people to get the shots.
"I know it's ambitious, twice our original goal, but no other country in the world has even come close," he added.
In addition, $10bn (£7.2bn) is going to be allocated expanding access to vaccines for the "highest-risk communities," Mr Biden said.
More than 545,000 Americans have died since the start of the pandemic while more than 30m people have caught the disease, making it easily the worst-hit country in the world.
Nearly half of schools from kindergarten through to eighth grade (13-14yr-olds) have opened for in-person learning, Mr Biden said, quoting a department of education report.
It means the US has almost met another of his targets - that of having a majority of such schools fully operational within the same 100-day deadline.
Mr Biden has been in the White House since 20 January - and he is holding his first formal news conference more than two months after taking office.
That makes him the first president in four decades to reach this point in his term without having conducted such a question-and-answer session.
A further $15 million (£11m) is being sent to help Palestine with its COVID-19 response in the West Bank and Gaza Strip, the US State Department said in a statement on Thursday.
The funds from the US Agency for International Development (USAID) would help support efforts by the Catholic Relief
Services in healthcare facilities as well as address food insecurity, the statement said.
