The Massachusetts Institute of Technology announced today it will suspend collaborations, including research projects and funding, with Huawei Technologies and ZTE, two Chinese tech companies fighting with the U.S. government over alleged sanction violations.

In a public letter titled “New review process for ‘elevated-risk’ international proposals,” MIT vice president for research Maria T. Zuber wrote that the school recently “determined that engagements with certain countries—currently China, Russia and Saudi Arabia—merit additional faculty and administrative review beyond the usual evaluations that all international projects receive.”

As a result of the enhanced review process, the university is “not accepting new engagements or renewing existing ones with Huawei and ZTE or their respective subsidiaries due to federal investigations regarding violations of sanction restrictions. The Institute will revisit collaborations with these entities as circumstances dictate.”

In January, Oxford University said it will stop taking funding from Huawei because of “public concerns raised in recent months surrounding UK partnerships with Huawei.”

Huawei and ZTE have been scrutinized by the U.S. over espionage risks since 2011, when the U.S. House of Representatives Intelligence Committee launched an investigation (later recommending that they be shut out of the U.S. market).

As the trade war with China intensified, however, the government began to home in on both companies. Last December, Huawei chief financial officer Meng Wanzhou (the daughter of Huawei founder Ren Zhengfei) was arrested in Canada at the request of the U.S. on charges of violating U.S. trade sanctions against Iran (Meng and Huawei have denied the charges). Earlier last year, ZTE agreed to pay a $1 billion fine to settle charges by the U.S. that it had violated sanctions by selling telecom technology to Iran and North Korea.

TechCrunch has contacted Huawei and ZTE for comment.