President Donald Trump is scheduled on Thursday to host Germany's newly elected chancellor, Friedrich Merz, in the Oval Office.

The pair in their first face-to-fact meeting are likely to discuss U.S. and European support for Ukraine's defense against Russia, along with trade issues, including the Trump administration's international tariffs.

"Our alliance with America was, is, and remains of paramount importance for the security, freedom, and prosperity in Europe," Merz said in a social media post in German. "The USA is an indispensable friend and partner of Germany."

In the latest escalation of the White House’s fight with Harvard University, President Donald Trump signed a proclamation Wednesday blocking foreign students from entering the U.S. to attend the school.

Trump invoked the Immigration and Nationality Act to prohibit the entry of noncitizens from entering the U.S. to study at Harvard for at least six months, arguing the institution is "no longer a trustworthy steward" of international students.

The proclamation also directed the secretary of state to consider revoking the visas of foreign students already in the U.S. to study at Harvard.

"I have determined that the entry of the class of foreign nationals described above is detrimental to the interests of the United States because, in my judgment, Harvard’s conduct has rendered it an unsuitable destination for foreign students and researchers," the proclamation said.

Last month, the Department of Homeland Security tried to revoke Harvard’s Student and Exchange Visitor Program last month -- which allows the school to sponsor foreign students – a federal judge issued a temporary order blocking the move.

Trump justified the sudden move Wednesday by claiming Harvard has refused to provide information about international students, has "extensive entanglements with foreign countries," and has discriminated in their admissions practices. The proclamation also noted that crime rates have "drastically risen" at the school and requires the government to probe the potential misconduct of foreign students.

"These concerns have compelled the Federal Government to conclude that Harvard University is no longer a trustworthy steward of international student and exchange visitor programs," the proclamation said.

A federal appeals court on Wednesday denied a request from President Donald Trump's administration to lift a lower court’s order that blocked the president’s efforts to allegedly dismantle the Department of Education.

A three-judge panel on the First Circuit Court of Appeals found “no basis on which to conclude” a federal judge erred when he issued a preliminary injunction last month blocking the effort to lay off half of the Department of Education’s employees.

“What is at stake in this case, the District Court found, was whether a nearly half-century-old cabinet department would be permitted to carry out its statutorily assigned functions or prevented from doing so by a mass termination of employees aimed at implementing the effective closure of that department,” the judges wrote in the order.

The court said there is “no force” to the Trump administration’s contention that the lower court’s order would cause them any irreparable injury by "undermining implementation of an important presidential policy."

Next stop, the United States Supreme Court.

-ABC News' Peter Charalambous

President Donald Trump has ordered Attorney General Pam Bondi to investigate whether former President Joe Biden's administration sought to conspire to cover up his mental state while in office.

This represents a significant escalation from the White House as it is a directive to the Justice Department to formally investigate. It goes beyond the review into Biden's last-minute pardons before leaving office

The president is directing the attorney general, in coordination with his White House counsel, to investigate "the circumstances surrounding Biden's supposed execution of numerous executive actions during his final years in office."

Former President Joe Biden responded to Trump's memo in a statement sent to ABC News.

"Let me be clear: I made the decisions during my presidency," Biden's statement said. "I made the decisions about the pardons, executive orders, legislation, and proclamations. Any suggestion that I didn't is ridiculous and false."

The statement went on to say: "This is nothing more than a distraction by Donald Trump and Congressional Republicans who are working to push disastrous legislation that would cut essential programs like Medicaid and raise costs on American families, all to pay for tax breaks for the ultra-wealthy and big corporations."

-ABC News' Katherine Faulders and Brittany Shepherd