A decision by the Obama administration to transfer money toward fighting Zika has hyper-charged the political battle over emergency funding.

Health and Human Services Secretary Sylvia Burwell announced Thursday that she is using her transfer authority to reallocate $81 million within the National Institutes of Health and Biomedical Advanced Research and Development Authority for anti-Zika efforts, including developing a vaccine for the virus.

The office of House Speaker Paul Ryan responded by accusing HHS of ignoring previous requests by Republicans to transfer the funds, saying it's only now doing so at the request of Democrats. The move shows the Obama administration is playing politics with Zika funding, according to Ryan's office.

"It reeks of pure politics that the administration denies Republican requests to reprogram resources but will act swiftly to do so once Democrats request it," said Ryan spokeswoman AshLee Strong. "But what else can we expect from a party that is blocking an additional $1.1 billion in funding to fight Zika purely to create a political issue."

Florida health officials have found several dozen cases of mosquito-borne infections, the first in the country. More than 1,825 cases have been reported in the U.S., including more than 400 pregnant women whose fetuses are at risk for severe birth defects from the virus.

HHS is transferring the funds from other areas so that researchers can work on developing a Zika vaccine, as Congress has not allocated emergency funds, Burwell wrote to congressional leaders on Thursday. But Burwell said she's unable to allocate any additional funds to Zika efforts beyond that $81 million. President Obama has requested $1.9 billion in emergency funds to fight Zika.

"With the actions described above, we have exhausted our ability to even provide short-term financing to help fight Zika," Burwell wrote. "Our nation's ability to mount the type of Zika response the American people deserve sits squarely with Congress."

Congressional Democrats and Republicans, who are on a seven-week summer recess, have continued to blame each other for failing to appropriate extra Zika funding. Senate Democrats blocked a $1.1 billion House measure because it continued extra rules for how the money could be spent, including a ban on sending any money to Planned Parenthood.

House Minority Leader Nancy Pelosi said by their actions, Republicans are forcing HHS to "raid critical health initiatives."

"Not only are these resources coming out of commitments to the fight against other devastating illnesses, they are nowhere near sufficient to address the Zika crisis with the seriousness it requires," Pelosi said.