Authorities say it's unclear why fewer migrants making unauthorized border crossings

Biden administration officials said Monday that the numbers of migrants making unauthorized border crossings over the weekend continued to be significantly lower than expected but they were not ready to declare their plan a success just yet.

"I think it's -- it's still too early to draw firm conclusions," Assistant Secretary for Border and Immigration Policy Blas Nuñez-Neto said in response to questions about the decline seen since last Thursday when the pandemic-era policy that allowed migrants to be quickly expelled ended.

"We are closely watching what's happening. We are confident that, you know, the plan that we have developed across the U.S. government to address these flows will work over time," he told reporters on Monday.

U.S. Border Patrol agents made 14,752 migrant apprehensions in the past 72 hours, Border Patrol Chief Raul Ortiz said in a tweet Monday.

Unauthorized crossings had reached more than 10,000 per day last week -- and President Joe Biden said then he expected the border to be "chaotic for a while," despite measures by border authorities to contain a surge in migration.

Homeland Security Secretary Alejandro Mayorkas told ABC "This Week" co-anchor Jonathan Karl on Sunday the decline was about 50% from levels seen just before the Title 42 policy lifted last week.

As ABC News has reported, some data suggests the Title 42 expulsion order may have caused more border crossings, not fewer. The data showed significantly higher repeat crossing attempts under Title 42, compared to standard immigration processing under Title 8 of the U.S. Code.

Since Friday, Title 8 now dictates the way all migrants at the border are processed.

"And it is important to note, that while Title 42 has ended, the conditions that are causing hemispheric migration at unprecedented levels have not changed," Nuñez-Neto said. "We continue to see more displaced people in the hemisphere than we have in decades."

There are many factors that cause migrants to make the dangerous journey north, including high levels of violence and economic instability across Latin America. More than 100 million people are displaced globally, including 20 million in the Western Hemisphere, according to the State Department.

"Migration impacts every single country in the region, and no one country can provide solutions for millions of displaced people on their own," State Department Principal Deputy Assistant Secretary Marta Youth said Monday.

Mexico and Guatemala have surged their own law enforcement and military personnel in recent days while administration officials continue to tout the effectiveness of the parole pathways that allow migrants to temporarily enter the country and claim asylum.

Homeland Security over the weekend returned "hundreds" of migrants to Mexico, including Venezuelans, Cubans and Nicaraguans. Thousands more were repatriated to other countries, Nuñez-Neto said, adding that Title 8 deportations are occurring "much more quickly" than before.

Administration officials have pointed to new options for legal immigration including proposals for foreign migrant processing centers.

However, a spokesperson for Guatemalan President Alejandro Giammattei said the government had not received any official requests from the U.S. government to create special processing centers for migrants trying to cross borders and eventually cross into the U.S.

"The government of Guatemala has not received any official requests for creating any kind of reception center yet," Guatemalan government spokesman Kevin Lopez Oliva told ABC News in an interview Friday.

"We just made a proposal to Secretary Mayorkas in a call, in a just unique call that just recently happened last week" between the Guatemalan President and the US Secretary of Homeland Security, "in which we were proposing an approach, an integral approach between the two countries," he added.

The approach proposed by the Guatemalan government includes "logistics support" from the U.S., Oliva said.

ABC News' Haroldo Martinez contributed to this report.