Hillary Clinton, visiting Florida, is expected to call on Congress on Tuesday to cut short its summer recess and pass funding to fight the Zika virus.
Florida's congressional delegation does not appear to need persuading.
Republican Gov. Rick Scott said Tuesday that the state's Department of Health has identified four more people in Florida with the virus who likely contracted it through a mosquito bite, bringing the total number of people with locally transmitted Zika to 21.
"This is not only an issue affecting us here in Florida — this is a national issue," Scott said. "The federal government must stop playing politics and Congress needs to immediately come back to session to resolve this."
Late last month, Florida authorities reported what was believed to be the first evidence of local Zika transmission in the continental United States. Soon after, the state identified at least 10 more cases caused by mosquitoes in the Miami-Broward area.
The federal government's response has so far been slow. President Barack Obama has requested $1.9 billion for several preventative measures, and a Republican-drafted plan to allocate $1.1 billion failed recently in the Senate when Democrats objected to funding cuts for other health programs. On Thursday, Obama said federal funds to fight Zika are quickly running out.
Action does not appear to be imminent, with Congress on its legally mandated August recess. But that hasn't stopped members of the Sunshine State's congressional delegation from calling on their colleagues to cut the vacation short to help fight the virus that causes birth defects.
"There are lives at stake and the problem gets worse literally every day," Rep. Alan Grayson told CNBC. "Every single day means more Zika babies and more deaths. The technology that can end this crisis is well understood."
Grayson, who is running in the Democratic primary for U.S. Senate, has held a town hall about the virus. He also called on House Speaker Paul Ryan to end the summer recess and bring Congress back to pass a "clean Zika bill."
His opponent in the primary, Rep. Patrick Murphy, said he was "extremely disappointed that congressional leaders decided to leave for the summer without passing critical Zika funding."
Democratic Rep. Gwen Graham of northern Florida also demanded that Congress cut short its vacation. "As the third largest [congressional] delegation in the country, if we work together we can make a big difference," she said in a statement.
Republicans also want action.
In a radio interview Monday, Republican Sen. Marco Rubio said that "Congress needs to come back and get something done, actually pass a bill that has more money. ...So that's why I am calling for Congress to go back this month and get it done quickly."
"We've been saying for months how important it is to get out in front of this thing and nip it in the bud," Republican Rep. Richard Nugent said in a statement. "Zika could easily get out of hand and right now, the response has been overwhelmingly penny-wise and pound-foolish. It's past time to get those resources out in the field."
Scott has also complained about the lack of action in Washington. While he acknowledged that Obama has offered $5.6 million to Florida while Congress is on recess, he said the president must work with lawmakers on a deal for more substantial funding.
Democrat Murphy said: "I stand with the president in urging Congress to do its job and immediately address this crisis. Our families deserve nothing less."
UPDATED: This story was updated to include comments from Sen. Marco Rubio and Gov. Rick Scott.
—CNBC's Tom DiChristopher and Reuters contributed to this report.