China Central Television, the mainstream broadcaster on the Chinese mainland, has made public three spying cases involving Taiwan intelligence agencies since the weekend. The spies targeted mainland students in an attempt to obtain classified information from them. CCTV also said the Ministry of State Security has cracked more than 100 such cases.

The latest report was broadcast on Sept 15, which marked the 18th National Defense Education Day, following which several mainland universities have advised their students to watch the CCTV series to learn more about the spying case and enhance their knowledge about personal and national security.

The exposure of Taiwan spies suggests cross-Straits relations have become increasingly complex and serious.

The relationship between the mainland and Taiwan has been cold at best ever since Tsai Ing-wen assumed office in 2016, because unlike her predecessor, she has not acknowledged the 1992 Consensus. With the support of other "pro-independence" leaders on the island, she and her administration have often challenged cross-Straits relations and surely have increased the number of spies.

In fact, after the spying racket was exposed, Tsai said the mainland victims had fabricated the news on social media and blamed them for whatever had happened, inviting severe criticism for her hypocrisy.

Taiwan is scheduled to hold local elections in November, a midterm test for Tsai. But the Democratic Progressive Party is known for triggering political conflicts before elections in an attempt to gain more votes. No wonder Tsai has denied the island's role in the spying racket－as she believes rebuttal will win her voters' empathy and thus more ballots.

Educational exchanges across the Straits have increased since 2008. As a growing number of mainland students have been allowed to pursue college degrees in Taiwan, academic and cultural exchanges between the youth from the two sides have expanded.

But instead of cherishing the hard-won fruits, the Tsai administration has set honey traps for innocent exchange students in an attempt to extract sensitive information about the mainland from them.

The expanding espionage network of Taiwan and some island leaders' "secessionist activities", combined with security investigations into some members of New Party, a pro-unification party on the island, have forced the mainland to take measures to subdue the provocative actions of the "pro-independence" forces.

It's time the Tsai administration stopped playing dirty games and further undermining cross-Straits ties for its partisan gains.

Zhu Songling is a professor at the Institute of Taiwan Studies of Beijing Union University. This is an excerpt from his interview with China Daily's Yao Yuxin.