President Joe Biden will host Costa Rica's President Rodrigo Chaves Robles Tuesday at a critical time for a region grappling with a record number of migrants heading to the United States.

The unprecedented movement of people in the Western Hemisphere has placed immense pressure on the Biden administration, which -- despite rolling out a series of measures to stem migration -- is still facing potentially thousands more people arriving at the US southern border this fall, placing a politically delicate issue at the forefront on the cusp of a presidential election.

The number of migrants crossing the treacherous Darien Gap -- which connects Panama and Colombia and has recently served as a barometer for movement in the region -- broke a new record this year. According to authorities, 248,901 people crossed the jungle in 2023, and of those, approximately 20% are children and adolescents.

"We're monitoring it really closely and are concerned," a senior administration official told CNN. "This has been a high priority for the US and for our partners in the region."

Already, border officials are seeing an increasing number of daily encounters at the border compared to earlier this summer. In July, the number of families apprehended at the border -- one of the most vulnerable populations -- nearly doubled compared to June, raising concerns within the Biden administration.

Tuesday's visit to the White House by Chaves Robles underscores the significance of US relationships in the Western Hemisphere to manage the flow of migrants.

In a statement, White House press secretary Karine Jean-Pierre said Biden and Robles will discuss how the US and Costa Rica "can build out inclusive and sustainable economies, including through the Americas Partnership for Economic Prosperity, advance democratic values in the region, promote safe and orderly migration in line with the principles of the Los Angeles Declaration on Migration and Protection and address regional security challenges."

Administration officials have frequently cited the Los Angeles declaration -- an agreement signed last year by countries in the Western Hemisphere, including Costa Rica -- as a step toward managing migration in the region and a commitment by regional partners to coordinate in that effort.

Costa Rica, which neighbors Panama, is among the countries through which migrants often transit on their way to the US southern border and is key to the administration's migration plans. An agreement between the US and Costa Rica struck under the Biden administration outlined broad commitments to strengthen enforcement, exchange information on flows and stabilize host communities, CNN previously reported.

But Costa Rica has also been overwhelmed by migrant arrivals -- underscoring the challenge facing US officials who are in part relying on countries with limited resources to provide legal pathways and discourage migration northbound. Costa Rica is also a destination for asylum seekers.

"We know Costa Rica has been impacted by migration," the senior administration official said, citing an influx of Nicaraguans and Venezuelans but commending Costa Rica as a "model and champion for a hemispheric approach."

Costa Rica is among a host of countries set to open so-called safe mobility offices, a new initiative by the Biden administration to partner with international organizations to establish brick-and-mortar processing centers for migrants to apply to migrate legally to the US, among other countries, instead of journeying to the border. A web portal was also launched for people to register and apply for programs and legal pathways before going to an office.

As of August 28, more than 38,000 individuals have registered in Colombia, Costa Rica and Guatemala for the Safe Mobility initiative, according to a White House official.

The US has historically worked closely with Costa Rica and it will continue to have a vital role, according to Andrew Selee, president of the Migration Policy Institute, a nonpartisan think tank.

"It's the one country, besides Mexico and Colombia, that has some real capacity," Selee said.

The safe mobility offices are one of many efforts launched in the region. Earlier this year, the administration also set joint efforts, with Panama and Colombia, into motion to try to end the movement of people in the Darien Gap. But experts warn that any significant enforcement would be difficult to execute given limited resources, requiring countries, like the US and Costa Rica, to work together to help people legally migrate to their destination instead of taking the dangerous journey north.