The government already has cancelled more than $US2.6 billion in federal research grants for the Ivy League school, which has pushed back on the administration's demands for changes to several of its policies.
A letter sent from the General Services Administration, which oversees contracting and real estate for the federal government, directed agencies to review contracts with the university and seek alternate arrangements.
President Donald Trump has railed against Harvard, calling it a hotbed of liberalism and antisemitism. The school filed a lawsuit April 21 over the administration's calls for changes to the university's leadership, governance and admissions policies. Since then, the administration has slashed the school's federal funding, moved to cut off enrolment of international students and threatened its tax-exempt status.
The administration has identified about 30 contracts across nine agencies to be reviewed for cancellation, according to an administration official who provided details on the condition of anonymity.
The contracts total roughly $US100 million, according to a senior administration official. The contracts include executive training for Department of Homeland Security officials, research on health outcomes related to energy drinks and a contract for graduate student research services.
Agencies with contracts that are deemed critical are being directed not to halt them immediately, but to devise a plan to transition to a different vendor other than Harvard.
The letter applies only to federal contracts with Harvard and not its remaining research grants.
Trump laid into Harvard on social media over the weekend, threatening to cut an additional $US3 billion in federal grants and give it to trade schools across the United States. He did not explain which grants he was referring to or how they could be reallocated.
The president also accused Harvard of refusing to release the names of its foreign students. In a new line of attack, he argued that students' home countries pay nothing toward their education and that some of the countries are "not at all friendly to the United States."
International students are not eligible for federal financial aid, but Harvard offers its own aid to foreign and domestic students alike.
"We are still waiting for the Foreign Student Lists from Harvard so that we can determine, after a ridiculous expenditure of BILLIONS OF DOLLARS, how many radicalised lunatics, troublemakers all, should not be let back into our Country," Trump said on social media.
It was not clear exactly what the president was referring to. The federal government already has access to visa information and other records on foreign students at Harvard and other universities.
The Department of Homeland Security has demanded that Harvard turn over a trove of files related to its foreign students, including disciplinary records and records related to "dangerous or violent activity."
