President Donald Trump's administration says it will "aggressively" revoke the visas of Chinese students studying in the US.

Secretary of State Marco Rubio said in a statement that the move would include "those with connections to the Chinese Communist Party or studying in critical fields".

Criteria will also be revised to "enhance scrutiny" of future visa applicants from China and Hong Kong, Rubio added.

Relations between Beijing and Washington have plummeted in recent months as a tit-for-tat trade war erupted between the two superpowers, sparked by Trump's tariffs.

On Monday, Rubio, who is America's top diplomat, ordered US embassies around the world to stop scheduling appointments for student visas as the state department prepares to expand social media vetting of such applicants.

Estimates indicate that around 280,000 Chinese students were studying in the US last year.

Chinese nationals used to account for the bulk of international students enrolled at US universities, though that has recently changed.

From pandemic-era restrictions to worsening relations between the two countries, their number has dropped in recent years, according to US State Department data.

Rubio said in Wednesday's statement: "Under President Trump's leadership, the US 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.

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

The Trump administration has already moved to deport a number of foreign students, while revoking thousands of visas for others. Many of these actions have been blocked by the courts.

It has also frozen hundreds of millions of dollars in funding for universities. The president sees some of America's most elite institutions, such as Harvard, as too liberal and accuses them of failing to combat antisemitism on campus.

Many US universities rely on foreign students for a significant chunk of their funding - as those scholars often pay higher tuition fees.

A number of international students have been reeling from the planned visa changes.

Some told the BBC they wished they had never opted to study in the US.

"I already regret it," said a 22-year-old master's student from Shanghai, who did not want to be named for fear of jeopardising a visa to study at the University of Pennsylvania.

An official memo, reviewed by the BBC's US partner CBS News, has instructed US embassies across the world to remove all open appointments for students seeking visas, but to keep already-scheduled appointments in place.

Beijing has not yet responded to the US move to revoke the visas of Chinese students specifically.

But China responded earlier on Wednesday to the Trump administration's move to cancel student visa appointments.

"We urge the US side to earnestly safeguard the legitimate rights and interests of international students, including those from China," an official was quoted as saying.

Last week, a judge temporarily blocked the Trump administration's attempt to strip Harvard of its ability to enrol international students.

The ruling came after America's oldest university filed a lawsuit against the administration. The White House accused the judge hearing the case of having a "liberal agenda".

On Wednesday, Harvard said in a court filing that revoking its certification to host international students could inflict irreparable harm on the university.

In a declaration filed with the court motion, Harvard international office director Maureen Martin said the move was causing "significant emotional distress" for students and scholars.

She wrote that students were skipping graduation ceremonies, cancelling international travel and in some cases seeking transfer to other colleges.

Some had also reported fears of being forced to return to countries where they face active conflict or political persecution, according to the court filing.