Liu Jieyi, director of the Taiwan Affairs Office of the State Council, said that "the objective of the maneuvers is to ensure the sovereignty and territorial integrity of China".
Last week, Xi presided over a massive show of force in the South China Sea conducted by the Chinese navy.
Taiwan has no intention of getting involved in a trade war between the U.S. and China, but launching a probe into Chinese steel products is expected to ensure that Beijing can not use Taiwan as a transit point to sell its cheap steel products in the USA market, Customs Administration Deputy Director-General Hsieh Ling-yuan (謝玲媛) said.
Taiwan's Defence Ministry said on Wednesday afternoon two Chinese H-6K bombers had flown around the island, passing first through the Miyako Strait to Taiwan's northeast and then back to base via the Bashi Channel between Taiwan and the Philippines.
Chinese state-linked media the Global Times reported that the exercises come in direct response to "provocations" by Taiwanese leaders related to what Beijing fears is a push for formal independence.
Chen told Reuters that the ministry was monitoring the situation and did not plan to issue an alert at this point. "It's the cheapest way of verbal intimidation and sabre-rattling", Major-General Chen said, adding that such exercises had been held every year since 2007, except for last year.
Ms Tsai's Democratic Progressive Party is traditionally pro-independence and her newly appointed premier William Lai is a longstanding independence advocate.
Beijing, which has always maintained its "One China" policy, sees Taiwan as part of China.
China fears she wants to push for the island's formal independence.
That same day, China's sole operational aircraft carrier, the Liaoning, sailed through the Taiwan Strait.
Beijing insisted that Washington correct its actions and stop maintaining official contacts with Taipei so as not to damage Sino-US relations and undermine peace and stability in the Taiwan Strait.
The naval exercises take place a month after the United States authorities approved the 'Law on Travel to Taiwan', called to stimulate mutual official visits with Taiwan at all levels and strengthen relations between Washington and Taipei.
Beijing has stepped up military patrols around Taiwan and used diplomatic pressure to isolate Taiwan internationally since Tsai took office, with Panama switching allegiance to China past year.