Beijing has accused Tsai Ing-wen, who took office on Friday as Taiwan's new leader, of taking an ambiguous stand on the one-China principle in a speech after she was sworn in, thereby bringing uncertainty to cross-Straits relations.

Tsai, Taiwan's first female leader, did not explicitly recognize the 1992 Consensus, which says that both sides are part of one China, the Taiwan Affairs Office of the State Council said in a statement after Tsai took office.

She also failed to put forward concrete ways to ensure the peaceful and stable development of cross-Straits relations, it said, adding that her remarks were an "incomplete answer sheet".

Tsai, chairwoman of the Democratic Progressive Party, defeated Kuomintang candidate Eric Chu and People First Party Chairman James Soong in January to become the island's top leader.

In her 25-minute speech, Tsai mentioned the talks between the mainland's Association for Relations Across the Taiwan Straits and the island's Straits Exchange Foundation in 1992, and conceded that those talks reached a common understanding.

She said the new leadership on the island will continue pushing forward the peaceful development of cross-Straits relations and maintain existing cross-Straits exchanges and communication.

The Taiwan Affairs Office of the State Council said the Taiwan leader has to choose between upholding the one China principle and pursuing "Taiwan independence", which will lead to a different future.

The Taiwan authorities must make the choice with concrete actions and face the test of history and the people, according to the statement.

Li Yihu, head of Peking University's Taiwan Institute, said, "Tsai mentioned seeking common ground while reserving differences in the cross-Straits relations, without saying what is the common ground."

"The island's new leader has to answer whether she endorses the 1992 Consensus. It's not an optional question," said Li. "The question must be answered with actions."

Li said the mainland won't tolerate any vagueness regarding the consensus, without which the peaceful development of the relations would be off course and would founder.

Ni Yongjie, deputy director of Shanghai's Taiwan Research Institute, said, "As Tsai mentioned in her speech, Taiwan has many problems. ... Her top priority will be reviving the island's flagging economy".

Ni noted that Taiwan's economy grew by less than 1 percent last year.

"Refusing to endorse the 1992 Consensus not only sabotages the political foundation and trust between the two sides, but also destroys prospects for economic exchange and cooperation," he said. "As a result, the interests of people from both sides will be hurt."

Zhang Guanhua, deputy director of the Institute of Taiwan Studies of the Chinese Academy of Social Sciences, said cross-Straits relations might enter a "cold" stage after Tsai's taking office, with cooperation and communication likely to be suspended.

　　Timeline of cross-Straits relations

January 1979

The mainland's top legislature issues a statement asking for an end to military confrontation across the Straits.

October 1987

Taiwan allows its residents to visit their families on the mainland for the first time since 1949.

October-December 1992

The mainland's Association for Relations Across the Taiwan Straits and Taiwan's Straits Exchange Foundation meet in Hong Kong and agree on the 1992 Consensus.

April 27-29, 1993

ARATS Chairman Wang Daohan and SEF Chairman Koo Chen-fu meet in Singapore.

April 29, 2005

Hu Jintao, general secretary of the Communist Party of China Central Committee, meets with Kuomintang Honorary Chairman Lien Chan in Beijing.

June 11-14, 2008

A delegation headed by Taiwan-based SEF Chairman Chiang Pin-kung visits Beijing for talks with Chen Yunlin, head of ARATS, marking the resumption of cross-Straits institutional consultations after a nine-year suspension.

Nov 3-7, 2008

Chen Yunlin leads a delegation to Taiwan to discuss issues including increasing direct flights, opening direct cargo shipping routes and fully opening postal services. On Dec 15, 2008, the Three Links (mail, transportation and trade) are officially launched.

June 2010

The Economic Cooperation Framework Agreement, a preferential trade agreement, is signed to reduce tariffs and commercial barriers.

November 2015

President Xi Jinping and Taiwan leader Ma Ying-jeou meet in Singapore.