New York, Dec 5 (IANS): The next US administration should rectify "costly and consequential" federal policies which have damaged American universities' ability to attract top academic talent from around the globe, Lee C. Bollinger, President of Columbia University, has urged.

In an open letter to President-elect Joe Biden, Bollinger said thousands of international students are unable to return to the US and "if they are able to gain entry, they face onerous restrictions that threaten their ability to pursue their academic careers", reports Xinhua news agency.

"Of greatest concern, there has been a sustained assault against the vibrant exchange with the international community," Bollinger said.

It is a grave mistake to turn international students away or hinder their ranks, said Bollinger who sees international students as being "utterly foundational to our pursuit of excellence in American higher education".

In the past four years, the federal government has erected barriers to foreign students coming to the US, cut the length of their stay, and curbed their ability to work here after completing their studies, Bollinger said.

Hence, "our ability to attract the greatest academic and scientific talents from around the globe, whether in the form of promising students or gifted faculty members", has been eroded, he said, urging Biden to take action against this serious threat as soon as possible after his inauguration in January.

Bollinger called for reforms, including reinstating the Deferred Action for Childhood Arrivals, expanding H-1B visas to restore postgraduate opportunities for international students, repealing travel ban on designated countries, and reducing the backlog of requested visa renewals and applications.

He also asked that the next administration to allow sufficient duration of stay for international students to complete degree programs, and work with Congress to address long-term challenges facing international students and faculty.

Prior to the Covid-19 pandemic, over 1 million international students came to the US each year to study, accounting for more than $40 billion of economic activity annually, according to Bollinger.