Washington — The Trump administration has unveiled a $2.5 billion plan to fight the coronavirus outbreak, asking Congress for $1.8 billion in new funding to boost the domestic and international response to the growing public health threat.

In a letter to Capitol Hill on Monday, Office of Management and Budget Acting Director Russell Vought said the administration is requesting a new appropriation of $1.25 billion, and permission to use $535 million in emergency funding that was originally intended to fight Ebola. By repurposing other funds, the plan would total $2.5 billion, including more than $1 billion to fund development of a vaccine.

"To this point, no agency has been inhibited in response efforts due to resources or authorities. However, much is still unknown about this virus and the disease it causes," Vought wrote in the letter. "The Administration believes additional Federal resources are necessary to take steps to prepare for a potential worsening of the situation in the United States."

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The number of confirmed global cases of coronavirus passed 80,000 on Tuesday, the vast majority of which are in China, where the outbreak originated. There are 14 confirmed cases in the U.S., not including 39 passengers of a cruise ship in Japan who tested positive and were brought back to the U.S. under the watch of federal health officials.

During a press conference in India on Tuesday, President Trump tried to reassure Americans that U.S. health officials are "very close to a vaccine" for the deadly coronavirus. But Republican Senators Roy Blunt and Bill Cassidy, who is a doctor, told reporters Tuesday a vaccine won't be available in the next 12 or 18 months, even as U.S. officials work tirelessly for a solution.

"I think we're approaching the vaccine as rapidly as any vaccine has ever been developed," Blunt told reporters on Capitol Hill Tuesday morning. "But that would still be a year or a year and a half before that vaccine would move beyond the trial stage. So we will not have a vaccine in the next 12 or 18 months."

"A year and a half would be the quickest that a vaccine has ever been developed for something like this," he added.

Cassidy spoke along similar lines, saying the hope in the U.S. is to keep the virus out of the country until a vaccine is developed.

"The hope is that we can push it off, as we learn, its entry into our country until we have the resources by which to mitigate," Cassidy said. "And that would be both a vaccine, which is going into phase one trial, they said in two months. That will be a year and a half until it's ready. But obviously if it is available in a year and a half, that's really progress."

Democrats on Capitol Hill said the administration's request was insufficient to meet the growing threat. Senate Minority Leader Chuck Schumer said the plan was "too little too late" and "indicative of his towering incompetence and further proof that he and his administration aren't taking the coronavirus crisis as seriously as they need to be."

"We've seen no sign that President Trump has any plan or urgency to deal with the spread of the coronavirus — we need real leadership and we need it fast," Schumer said in a statement. Mr. Trump reacted to Schumer in a tweet Tuesday morning.

"If I asked for more he would say it is too much. He didn't like my early travel closings. I was right. He is incompetent!" the president wrote.

Kristin Brown and Stephen Sanchez contributed to this report.