The White House on Thursday unveiled a sponsorship-focused program to streamline the acceptance of up to 100,000 Ukrainian refugees in the US, while warning them to avoid trying to come in via Mexico.

The “Uniting for Ukraine” initiative will launch via an online portal on April 25, senior officials from the Department of Homeland Security and National Security Council revealed before the official announcement.

Under the plan, organizations like churches and other civic groups will be able to identify Ukrainian nationals applying for humanitarian parole and coordinate with Americans wishing to help. Would-be sponsors will be able to upload an affidavit of support directly onto the portal system. 

Sponsors must be able to “attest to their ability” to support the various refugees and will be subject to background checks and screenings. 

Ukrainian refugees seeking parole through the program must have a sponsor to be approved. Parole will be granted on a case-by-case basis and last up to two years. 

In addition to an approved sponsorship, Ukrainian nationals must meet other requirements such as vaccinations for a “range of public health issues” and passing “robust biographic and biometric checks.” The refugees must also have been residents of Ukraine since Feb. 11.

President Biden formally announced the program Thursday morning after teasing the initial plan last month, saying it will “complement the existing legal pathways available to Ukranians.”   

“It will provide an expedient channel for secure, legal migration from Europe to the United States for Ukrainians who have a US sponsor, such as a family or an NGO,” he said. “This program will be fast.  It will be streamlined.  And it will ensure the United States honors its commitment to go to the Ukrainian people and need not go through our southern border.”

So far, 15,000 Ukrainian nationals have been accepted into the US over the last three months — with most arriving through the southern border with Mexico.

In March, DHS Secretary Alejandro Mayorkas declared that Ukrainian refugees seeking asylum would not be turned away at the border — despite the Trump-era Title 42 order remaining in place.

However, officials said the Mayorkas order would be revoked as of April 25 in an apparent attempt to keep parole claimants in the “Uniting for Ukraine” program.

“We would like to encourage all Ukrainian nationals who are seeking to come to the US to remain in Europe and take advantage of this program,” one senior official told reporters, adding that there would be “no preference” for those who have traveled to Mexico to cross via the border.

“Ukrainians who do seek to enter the United States at a land border without a visa, without completing the ‘Uniting for Ukraine’ process, may be refused entry under our existing laws,” the official added.

It is unclear how long the process of sponsorship and parole approval will take, but the officials insisted they anticipate the process to be “fairly quick.”

“We are essentially making it available for Ukrainians who have strong ties to the US,” one said. “The process will be a pretty streamlined process, and we are hoping will move pretty expeditiously for Ukrainians who have been — who have identified the sponsor as committed to providing financial support and other kinds of support.”

The administration did not reveal how many Ukrainian nationals they expect to apply for parole through the sponsorship program, but said it “will probably be the majority of the 100,000” planned to be taken in.

More than 5 million Ukrainians have fled their country following the Russian invasion of that began Feb. 24. The majority of evacuees have fled to neighboring European nations, such as Poland and Romania, for temporary resettlement.