In a show of apparent goodwill, Chinese president Xi Jinping and Ma met in Singapore in a historic meeting between the two sides in November last year.
With Ma's KMT out of the picture however, China is making its stance over Taiwan's sovereignty clear in an effort to press Tsai on her stand on the issue.
On Monday, China state-run news agency Xinhua reported a phone call between Chinese foreign minister Wang Yi and U.S. Secretary of State John Kerry during which Wang urged the U.S. to "abide by the one-China policy" and "properly handle the Taiwan issue."
In the weeks leading up Tsai's inauguration, China repatriated Taiwanese individuals suspected of perpetrating cyber crimes from Kenya and Malaysia. Their argument: most victims of the cyber crimes are on the mainland.
Taiwanese criminals "have been falsely presenting themselves as law enforcement officers to extort money from people on the Chinese mainland through telephone calls", China's Ministry of Public Security said in April when suspects were deported from Kenya to China.
In March, China's military commemorated a key victory over Taiwan's Nationalist forces in 1949.