Katie Tobin, a top figure in the White House focusing on migration issues, has announced her planned departure.

Serving for three years in the National Security Council, Tobin's role was significant, especially when she worked as the senior director for transborder security, as Fox News reported.

Despite initial plans to leave last summer, she extended her tenure until the end of the year.

That decision was reportedly made following requests from the Biden administration for her to stay on, according to NBC News.

Challenges at the Southern Border

The announcement of Tobin's resignation comes at a time when the Biden administration is under heavy scrutiny for its approach to the surge of illegal immigration at the southern border.

Tobin played a crucial role in this sector, notably participating in a U.S. delegation to Mexico aimed at discussing measures to reduce illegal border crossings.

Furthermore, she spearheaded the planning for the discontinuation of the Trump-era Title 42 last year.

Jake Sullivan, the National Security Advisor, lauded Tobin in a statement to NBC News.

He described her as "tenacious and dedicated" in her efforts on migration.

"We will miss Katie's positivity and thoughtful contributions on an incredibly complex portfolio, but wish her well," Sullivan added.

Unprecedented Migration Figures

Recent statistics from the southern border highlight the escalating crisis.

In a report by Fox News, sources from Customs and Border Protection disclosed that there were around 300,000 migrant encounters in the last month of 2023 alone, a figure previously considered unfathomable.

The period between Dec. 1 and 31 saw over 302,000 migrants attempting to cross into the U.S. through the southern border, marking the highest count for any single month on record.

This is also the first instance where migrant encounters have surpassed the 300,000 mark.

Border Patrol agents near El Paso, Texas, apprehended 40 migrants involved in two separate human smuggling operations this week.

Next Steps and Leadership Transition

As Tobin exits her role, the search for her successor is ongoing. An NSC spokesperson confirmed to NBC News that no replacement has been chosen yet.

This transition comes at a critical juncture, with the administration grappling with the complexities of border security and migration management and growing unease among the electorate.