Dr. Anthony Fauci, a top Obama administration doctor, exhorted Congress on Sunday to promptly agree to appropriate an additional roughly$ 2 billion to fight against Zika — the most recent in the back and forth between the White House and GOP-led House about fund against the deadly virus.

We have to act now, Fauci, director of the National Institute of Allergy and Infectious Diseases, told Fox News Sunday.

House Republican leaders have argued that the federal government has enough money now to fight the virus and that additional funding should come through the regular appropriations process this fall.

However, House Appropriations Committee Chairman Hal Rogers indicated last week that he would support immediate supplemental fund, with a White House request that includes a detailed spending plan.

We cant do it without the numbers, the Kentucky Republican told Wednesday on Capitol Hill.

While Rogers also has tried to assure the public that Congress will not let a public health crisis, he has suggested that the administration might not get all of the roughly$ 2 billion, which he has referred to as a slush fund.

I disagree with that, Fauci told, arguing the administration has presented Congress with a project-by-project approach and that it will also use money left from fighting the Ebola virus.

There has so far been no documented Zika infections in the United States from mosquitoes that carry the virus. But nearly 350 illness have been reported across all 50 nations, each linked to travel to Zika outbreak regions, largely the Caribbean and Latin America. Thirty-two of the infected girls were pregnant. The virus can also be spread through sex.

The regular appropriations process takes too long, Fauci told Sunday. I dont want to wait to have to develop a vaccine.

The House agreed late last week on a bipartisan measure to speed up development of a treatment.

However, on Friday, Democratic Reps. Nita Lowey, N.Y .; Rosa DeLauro, Conn .; and Debbie Wasserman Schultz, Fla ., exhorted Rogers to hold a special session on the administrations request for emergency supplemental funding.

Under the rules of the Appropriations Committee, three members may request the chairman convene a special session. If the chairman fails to schedule such a meeting within seven calendar days, a majority of the committee members may convene a special session on their own.

A Zika infection causes merely a mild and brief illness in most people. But in the past year, infections in pregnant women have been strongly linked to fetal demises and devastating birth defects, mostly in Brazil, where 1,113 cases of associated microcephaly have been confirmed since October.

The Associated Press contributed to this report.