Originally Published: 28 MAR 22 17:37 ET

Updated: 28 MAR 22 22:33 ET

By Priscilla Alvarez, CNN

(CNN) -- The Biden administration will offer Covid-19 vaccines to migrants taken into custody at the US-Mexico border, according to two sources familiar with the planning, and confirmed by the Department of Homeland Security, as officials prepare for an influx of migrants.

The plan, which had earlier been a source of tension at the White House, could extend to thousands of migrants encountered at the US southern border.

The Department of Homeland Security will be able to initially provide up to 2,700 vaccines per day, it said in a notice to Congress obtained by CNN, increasing to 6,000 daily by the end of May.

The decision comes as the Biden administration reassesses a Trump-era pandemic emergency rule, known as Title 42, that has allowed authorities to turn away migrants arrested at the border for more than two years.

As the pandemic landscape evolves, discussions about terminating that order have picked up speed, sources tell CNN, though it's also sparked concerns about a potential surge.

The US Centers for Disease Control and Prevention is expected to release its latest assessment of the authority in the coming days.

Offering the Covid-19 vaccine to migrants encountered at the US southern border would be an extension of what the Biden administration is already doing for migrants subject to the Trump-era "remain in Mexico" policy. Individuals subject to that policy and returned to Mexico are offered Covid-19 vaccines. As of March 23, more than 1,400 migrants have been sent back to Mexico under the "remain in Mexico" policy.

Last year, top White House officials rejected a proposal to vaccinate migrants -- a plan that had been intended to address public health concerns -- because they thought it would encourage more people to come to the US, sources told CNN.

Now, the administration is moving ahead.

"The effort to vaccinate those in our care and custody, which is a public health best practice, has been ongoing for many months. DHS has already taken steps to offer COVID-19 vaccines to noncitizens in (Immigrations and Customs Enforcement) custody," the department said in a statement.

"In order to further safeguard public health and ensure the safety of border communities, the workforce, and migrants, DHS will expand these efforts and begin providing age-appropriate COVID-19 vaccines to noncitizens taken into CBP custody at the Southwest land border who are determined to be inadmissible pursuant to Title 8," it added.

Border Patrol Chief Raul Ortiz told CNN last week that discussions about offering Covid-19 vaccines to migrants were ongoing.

"I think certainly vaccines are something that's going to be very, very important, especially with the communities that are affected," Ortiz said. "We have to ensure that as we apprehend individuals and that they are turned over to an NGO or released in the community that we've set them up for proper care."

This story has been updated with additional information.