Several foreign nations, notably China, push students flooded into U.S. colleges and universities to steal trade and defense secrets “whenever the opportunity presents itself,” according to a new report that highlights the threat to national security posed by foreign students.

The Center for Immigration Studies called foreign student visas a “weak point” in national security, and pointed a finger at China as a key abuser of the system, a claim made by several other immigration and national security groups.

It said that the explosion of student visas to STEM schools takes positions that U.S. students can use and puts potential spies inside institutions that have key national security ties to the U.S. government.

“Because there is no control over the number, place of origin, or courses and research studies of foreign students and exchange scholars, many of those governments use the U.S. foreign student and scholar programs as opportunities to engage in spying and theft of important defense and trade secrets, as well as cutting-edge technological advances. For many nations — China is a prime example — such espionage is a ‘family affair’ and it encourages all of its students and scholars to bring important information home whenever the opportunity presents itself,” said the report, shared with Secrets.

Countries with the worst numbers of overstay and worst rates of compliance - China in 2018 18,000 overstayed, top 5 countries represent 44% of all overstayers. @JessicaV_CIS — Center for Immigration Studies (@CIS_org) August 20, 2019

The center, which promotes immigration reform, released the report during a morning conference called to discuss the threat by foreign students, especially the thousands who overstay their visas.

While it noted that there can be a positive benefit to educating potential foreign leaders, the growing spy wars with China and other U.S. enemies should require a new focus on foreign students.

“An unknown number of them also engage in activities hostile to our country and communities. These activities range from participation in terrorism to espionage. Some of them are ‘sleepers’ put into place to be activated either by order of their masters, or upon some specific triggering event,” said the report based on federal reports and news stories.

“While the percentage and number of such individuals is undoubtedly small, it takes only a few aliens intent on serious harm to the United States to create a national tragedy,” added the report.

The center suggested that the administration put new limits on student and exchange visas and punish colleges and universities with high numbers of foreign students who overstay their visas.

The report said that nearly 70,000 foreign students overstayed their visas in 2017. Chinese students were first, with 18,075.