Senate Minority Leader Harry Reid of Nev., center, accompanied by Sen. Charles Schumer, D-N.Y., right, faces reporters on Capitol Hill in Washington, Tuesday, June 28, 2016, as the Senate split along party lines and left a $1.1 billion proposal to fight the Zika virus in limbo. (J. Scott Applewhite/AP)

Congressional efforts to fight the Zika virus failed Tuesday, as lawmakers accused each other of playing politics with a looming public health crisis while doctors and medical experts warned of the risk of an outbreak on the U.S. mainland.

Senate Democrats blocked a $1.1 billion funding package to fight the mosquito-borne virus because of “poison pill” measures added by Republicans on other issues. The clash raised serious doubts about whether Congress will heed warnings and allocate funds to fight Zika before lawmakers leave for an extended recess next month.

Each side said the other would be responsible if the money isn’t approved and the virus spreads in the country this summer. The issue could also become a factor in the November elections, particularly in states such as Florida and Texas where the mosquitoes that transmit the disease flourish.

The inaction came amid dire warnings from medical experts about Zika, which can cause devastating birth defects in babies whose mothers are infected while pregnant. Public health experts said money is desperately needed to develop a vaccine, educate the public and learn more about the virus, which can be spread through mosquitoes and through sexual activity.

“This is the ultimate playing politics with the public’s health and it’s really shameful and just unfortunate,” said Irwin Redlener, a pediatrician and director of the National Center for Disaster Preparedness at Columbia University.

Senate Majority Leader Mitch McConnell (Ky.), second from left, joined by, from left, Sen. Roy Blunt (R-Mo.), Sen. John Thune (R-S.D.) and Senate Majority Whip John Cornyn (R-Tex.) on Tuesday as a proposal to fight the Zika virus was left in limbo. (J. Scott Applewhite/AP)

The package that failed was negotiated between House and Senate Republicans after Democrats left bipartisan talks due to spending cuts included in the legislation and provisions to, among other things, block funding for Planned Parenthood and curb environmental regulations. President Obama originally asked for $1.9 billion to fight Zika in February.

“I don’t remember anything as outrageous, as shameful as this piece of legislation,” said Senate Minority Leader Harry M. Reid (D-Nev.).

Senate Majority Whip John Cornyn (R-Tex.) responded by standing on the Senate floor next to a large photo of an infant with microcephaly, a developmental defect linked to Zika that causes unusually small heads and often incomplete brain development.

“I’ll tell you what shameful is,” he said. “That’s allowing more women of child-bearing age to contract the Zika virus so their babies can end up looking like this.”

While Democrats have pushed for new negotiations, Cornyn told reporters this was the only chance to pass a measure to fight Zika. “This is the one shot,” Cornyn said. “There’s not going to be another opportunity to deal with this in the near future.”

Florida Sens. Marco Rubio (R), who is seeking reelection, and Bill Nelson (D) have both pushed for Zika funding, although Nelson voted against Tuesday’s package because of the Republican provisions. In a statement, Florida Gov. Rick Scott (R) blasted Congress and said the state allocated more than $26 million in funds last week for preparedness and prevention of the virus.

“It is time for Congress to stop playing politics with the health, safety and well-being of families in Florida and come together to address the serious threat of the Zika virus,” Scott said in a statement.

Jason Kander, who is running against Missouri Republican Roy Blunt, said in a statement that “Washington dysfunction has stopped Congress from responding to a public health crisis.”

Last month, Blunt helped orchestrate a bipartisan deal to fund Zika response efforts. But on Tuesday, he stood with other GOP leaders and urged Democrats to vote for the Republican deal instead.

Presumptive Democratic presidential nominee Hillary Clinton called on Congress to pass a deal and said funding is needed. She retweeted a message from her senior policy advisor, Ann O’Leary, that read: “Senate Dems are right: Public Health emergencies are not the place to inject harmful partisan policies.”

Clinton dispatched O’Leary and political director Amanda Renteria to meet with doctors and officials in Puerto Rico, and directed policy staff to focus on the issue.

The White House also blasted congressional Republicans.

“You would think that at some point the safety and well-being of pregnant women in the United States would be more important than politics to Republicans,” said White House Press Secretary Josh Earnest. “But unfortunately it’s not.”

Presumptive Republican presidential candidate Donald Trump has not talked about Zika and his campaign did not respond to a request for comment.

The virus has infected thousands of people in Puerto Rico and is lapping at the mainland’s shores: women in 46 Latin American and Caribbean countries where the virus is circulating have been advised by the World Health Organization to consider delaying pregnancy.

While no localized transmission has yet occurred in the continental United States, three women on the U.S. mainland have given birth to infants with Zika-related birth defects. The Centers for Disease Control is monitoring 265 pregnant women infected with the virus on the U.S. mainland and 189 in Puerto Rico.

“This is a public health emergency,” said Benard Dreyer, president of the American Academy of Pediatrics.

He said of Congress: “They just need to get their act together and act in a responsible way, in a bipartisan way, on an issue that is clearly extraordinarily impactful to children and their families, and do it immediately.”

Public health officials warned that even if funding were to pass Congress within the next week, much of it wouldn’t get to states and municipalities before September at the earliest. In most parts of the country, peak mosquito season is between June and early October.

“We’re not happy with it, obviously, because the more resources we can put toward preventing this disease rather than reacting to it . . . the more protected the American public will be,” said Joseph Conlon, technical adviser to the American Mosquito Control Association.

A coalition of nearly 40 groups — including the American Academy of Pediatrics, American Congress of Obstetricians and Gynecologists and Easter Seals — sent a letter this week urging Congress to pass a measure that would not place restrictions on Zika funding and that would allow the budget to be expanded in subsequent years.

“The fact that it is already almost July and Congress has failed to act would seem to reflect an appalling indifference to the lives of infants and their families,” it read.

The letter cited an April summit where Centers for Disease Control Director Thomas Frieden said caring for a single child with birth defects can cost at least $10 million.

“There’s a real aspect here of being penny wise and pound foolish,” said Cynthia Pellegrini, senior vice president of public policy at the March of Dimes, which signed the letter.

“We can pay now and do prevention or we can pay later,” she said.

Mike DeBonis and Kelsey Snell contributed to this report.