Senate Democrats on Tuesday blocked a $1.1 billion Zika-virus funding package drafted by congressional Republicans, citing politically motivated language aimed at Planned Parenthood and environmental regulations.

The partisan clash casts serious doubt on whether Congress will be able to heed increasingly dire warnings from public health officials and provide new funds to combat the virus before lawmakers leave Washington next month for an extended congressional recess.

Top Senate leaders appeared to be sharply at odds after the vote failed 52 to 48, with 60 votes needed to advance the legislation. Each side charged that the other would be responsible if money isn’t approved and the virus, which causes birth defects, begins to spread in the United States over the summer.

“This is the one shot,” Senate Majority Whip John Cornyn (R-Tex.) told reporters. “There’s not going to be another opportunity to deal with this in the near future.”

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

Cornyn then retorted on the floor, standing next to a large photo of an infant with microcephaly, a developmental defect linked to Zika and leading to abnormally small heads.

“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.”

Everything you ever wanted to know about the Zika virus and its spread across North and South America.

Cornyn called Democrats “sore losers” and accused them of betraying their previous calls for action, which date back to President Obama’s February request for $1.9 billion. “I frankly do not understand how Senate Democrats, having taken this position previously, can come in here and engage in a partisan filibuster to stop funding for this impending public health crisis,” Cornyn said.

Not all Republicans were willing to abandon the talks completely. Sen. Roy Blunt (R-Mo.) told reporters that he spoke with Sen. Patty Murray (D-Wash.) on Tuesday morning, leaving the door open for further talks.

“We’ll see what happens,” Blunt said. “I know we have to do something, and someone has to figure out how to do it.”

Blunt and Murray co-sponsored a bipartisan funding package that passed the Senate in May. That measure provided the same $1.1 billion funding level without the added restrictions and cuts opposed by Democrats.

The package that failed Tuesday was negotiated between House and Senate Republicans after Democrats left bipartisan talks because of spending cuts included in the legislation and what they viewed as “poison pill” political provisions, according to Democratic aides.

The House passed the bill early Thursday morning without debate as GOP leaders sought to short-circuit a Democratic floor protest over gun control.

Republicans’ decision to try to advance a GOP-only package was a setback after weeks of optimism that Congress would be able to fund measures to combat the spread of Zika before leaving for an extended summer break next month.

Sen. Charles E. Schumer (D-N.Y.) said Tuesday that the Republican bill was “filled with poison pills” and a “cynical maneuver” that stood no chance of being accepted by Democrats.

“What we want them to do is negotiate,” he said. “We’re willing to compromise. We already showed that in the previous bill that the Senate passed. . . . But what they’re doing is going to kill any chance of Zika [funding].”

Lawmakers in both parties could face blowback at home for failing to craft a consensus measure. Zika is linked to severe birth defects in babies of pregnant women who are infected with the virus. At least four women on the U.S. mainland have given birth to infants with birth defects related to Zika, and the Centers for Disease Control and Prevention is monitoring 265 women on the U.S. mainland and an additional 189 with Zika in Puerto Rico.

The House-passed measure would provide $1.1 billion to fight the mosquito-borne virus through September 2017, including funds to help develop a vaccine. The spending would be offset by $750 million in savings, including $107 million in unused Ebola funds, $100 million in cuts to administrative funding for the Department of Health and Human Services and $534 million from unspent Affordable Care Act money for health-care exchanges in U.S. territories.

The package also loosens Environmental Protection Agency restrictions on pesticides and strikes a measure that would have banned the display of the Confederate battle flag at cemeteries run by the Department of Veterans Affairs.

On Monday, Reid called the bill “nothing more than a goodie bag for the fringes of the Republican Party.” The White House has threatened to veto the legislation, and Democrats argue the additions were politically motivated and intended to kill the entire funding package.

“It’s like we’re being dared to oppose this legislation,” Reid said. “We have no choice.”

Senate Majority Leader Mitch McConnell (R-Ky.) charged Democrats on Monday with quibbling over minor provisions and standing in the way of spending that could help avert a public health crisis.

“There is no reason Democrats should reverse course now and block funding for Zika control in the midst of mosquito season,” McConnell said, noting the final legislation contains the same amount of funding as an earlier bipartisan Senate agreement. “There’s no reason they should put partisan politics above the health of pregnant women and babies.”

Reid shot back that GOP leaders were catering to the extreme wing of their party by including language in the package that would put restrictions on how the funding could be used by Planned Parenthood and by offsetting the cost of the legislation through spending cuts to the Affordable Care Act and to Ebola readiness efforts.

Following the vote, neither McConnell nor Reid gave any public indication that they were ready to begin a new set of negotiations. Senate Democrats made a last-minute attempt to salvage the legislation Tuesday morning by sending a letter to McConnell and House Speaker Paul D. Ryan (R-Wis.) requesting that they reopen negotiations.

“We stand ready to work cooperatively with you to address this national public health emergency,” they wrote.

Republican leaders have not formally responded, but any chance of new negotiations is slim. The House left town last week and will not return until after the July 4 holiday. Both chambers will be in for two weeks before heading out on a seven-week recess.