The US State Department said on Wednesday it is restarting the suspended process for foreigners applying for student visas, but all applicants will now be required to unlock their social media accounts for government review.

The States Department said consular officers will be on the lookout for posts and messages that could be deemed hostile to the United States, its government, culture, institutions or founding principles.

In a notice made public on Wednesday, the department said it had rescinded its May suspension of student visa processing but said new applicants who refuse to set their social media accounts to "public" and allow them to be reviewed may be rejected.

It said a refusal to do so could be a sign they are trying to evade the requirement or hide their online activity.

"The enhanced social media vetting will ensure we are properly screening every single person attempting to visit our country," a senior State Department official said.

The Trump administration last month temporarily halted the scheduling of new visa interviews for foreign students hoping to study in the US while preparing to expand the screening of their activity on social media, officials said.

Students around the world, including those from China, have been waiting anxiously for US consulates to reopen appointments for visa interviews, as the window left to book their travel and make housing arrangements narrows ahead of the start of the school year.

Jameel Jaffer, executive director at the Knight First Amendment Institute at Columbia University, said the new policy evokes the ideological vetting of the Cold War, when prominent artists and intellectuals were excluded from the US.

“This policy makes a censor of every consular officer, and it will inevitably chill legitimate political speech both inside and outside the United States," Jaffer said.

Student visas are one of a series of battles waged over higher education by the Trump administration, which has rescinded thousands of visas and sought to ban Harvard University from accepting international students. (Agencies)