U.S. Secretary of State Marco Rubio said Wednesday the U.S. will begin revoking the visas of some Chinese students, including those studying in "critical fields."

China is the second-largest country of origin for international students in the United States, behind only India. In the 2023-24 school year, more than 270,000 international students were from China, making up roughly a quarter of all foreign students in the United States.

"Under President Trump's leadership, the U.S. State Department will work with the Department of Homeland Security to aggressively revoke visas for Chinese students, including those with connections to the Chinese Communist Party or studying in critical fields," Rubio said in a statement.

The Chinese Embassy in Washington didn't immediately respond to a message seeking comment Wednesday night.

Scope of action unclear

Rubio's statement did not offer details on how extensively the visa revocations would be applied. Even a relatively small number could disrupt the flow of Chinese students seeking out higher education in the U.S. That phenomenon originally began as far back as the late 1970s.

Recent decades saw the United States become even more of a destination of choice for many Chinese students looking for an alternative to China's intensely competitive university system, drawn to the strong international reputation of U.S. schools. Those students typically come from wealthier families able to afford the high cost of U.S. universities.

Many of those have stayed after graduating and have been credited with contributing to American research capacity and the U.S. workforce.

The announcement came a day after Rubio halted the scheduling of new visa interviews for international students as the department prepares guidelines for increased vetting of their activity on social media.

Together, the announcements from the State Department added to uncertainty for America's international students, who have faced intensifying scrutiny from the Trump administration.

Earlier this year, U.S. Immigration and Customs Enforcement arrested and tried to deport students who had been involved in campus protests against the Israel-Hamas war. And the Trump administration abruptly terminated the legal status of thousands of international students before reversing itself and then expanding the grounds on which students can lose permission to study in the U.S.

More scrutiny for future applicants

In his announcement on China, Rubio said the government also will "revise visa criteria to enhance scrutiny of all future visa applications from the People's Republic of China and Hong Kong."

WATCH | U.S. halts scheduling of new visa interviews for international students: 

U.S. pauses new foreign student visa applications

Canadian students who want to study in the U.S. face a new hurdle. On Tuesday, U.S. Secretary of State Marco Rubio told U.S. consulates and embassies to pause foreign student visa applications. This is the latest escalation in a fight between the Trump administration and Ivy League universities.

Visa applicants have been required to provide social media handles to the U.S. State Department since 2019.

A cable sent to U.S. embassies and consulate Tuesday did not indicate what kind of additional scrutiny the new guidelines would cover, but suggested the new reviews may be more resource-intensive.

The additional vetting will deter students from coming to the U.S., said Jonathan Friedman of PEN America, a literary and free expression organization.

"The details remain vague, but this policy risks upending the long-standing place of the U.S. as a beacon for intellectual and cultural exchange with the world."