The State Department has opened an investigation into Harvard University's eligibility as a sponsor in the U.S. exchange visitor program, Secretary of State Marco Rubio said on Wednesday, as the Trump administration takes aim at the country's oldest and richest university.

WASHINGTON D.C. -The US State Department has said that it is opening an investigation into Harvard University’s continued eligibility as a sponsor for the Exchange Visitor Program, which allows foreign students and scholars to participate in exchange programs in the US.

Roughly one-quarter of Harvard's students are foreign, making the removal of their access to the university a potentially crippling blow.