An hour ahead of a federal hearing on Thursday over Harvard's ability to enroll international students, the acting director of the U.S. Immigration and Customs Enforcement issued a letter formally notifying the school that its Student and Exchange Visitor Program certification would be withdrawn.

The formal notice -- which provides Harvard University 30 days to respond -- said the Department of Homeland Security identified "national security concerns" related to international students and accused them of allowing antisemitism on campus.

"During a records review of Harvard University, compliance issues were identified that may result in the withdrawal of your school's certification and bar any further enrollment or education of nonimmigrant students," the notice said.

With a federal judge set to evaluate the legality of the Trump administration's actions last week revoking the school's ability to enroll international students, sources have described the letter as an effort to provide a legal justification for last week's purported revocation.

-ABC News' Peter Charalambous

The Trump administration will work to "aggressively revoke visas" for Chinese students at U.S. universities, including those with ties to the Chinese Communist Party or studying in "critical fields," Secretary of State Marco Rubio said in a statement Wednesday.

Rubio's statement said the State Department and the Department of Homeland Security would work on revoking visas.

"We will also revise visa criteria to enhance scrutiny of all future visa applications from the People’s Republic of China and Hong Kong," Rubio said.

The move is in step with the Trump administration's ongoing crackdown on student visas.

-ABC News' Shannon Kingston

A federal judge in Boston has ordered President Donald Trump's administration to resume processing immigration benefits for migrants paroled under several humanitarian parole programs that the Department of Homeland Security attempted to halt.

Judge Indira Talwani's decision is the latest ruling in a wide-ranging lawsuit that is challenging the Trump administration’s decision to halt processing applications from migrants who are already under these programs or are hoping to be.

It essentially means that beneficiaries of: Uniting for Ukraine, Operation Allies Welcome (Afghanistan), Central American Minors Parole, Family Reunification Parole, Military Parole-in-Place, and CHNV (Cubans, Haitians, Nicaraguans, Venezuelans) can continue applying for other types of relief.

Judge Talwani also ordered the administration to accept initial and re-parole applications for people under the Military Parole in Place Program (MPIP). That program allows some current and former members of the military and their relatives to apply for parole if they lack legal status.

-ABC News' Armando Tonatiuh Torres-García

Elon Musk is set to depart the Trump administration and leave his role as a special government employee, a White House official told ABC News.

The White House will begin Musk's off-boarding Wednesday evening, the official said.

Musk was named as a Special Government Employee by Trump, and was hired for 130 days to provide expertise that the administration didn't have internally. His 130-day period is set to expire on Friday.

Musk shared the update on X Wednesday night, thanking President Donald Trump and saying his Department of Government Efficiency team will continue to work throughout the government.

"As my scheduled time as a Special Government Employee comes to an end, I would like to thank President @realDonaldTrump for the opportunity to reduce wasteful spending," Musk wrote.

"The @DOGE mission will only strengthen over time as it becomes a way of life throughout the government," he added.

-ABC News' Will Steakin