Taiwan, as a nonmember of the World Health Organization, was denied observer status Monday on the first day of the virtual World Health Assembly for the fourth straight year due to China's firm opposition.

The self-ruled island's exclusion from the plenary meeting of the WHO's decision-making body came despite its success in containing the spread of the novel coronavirus, as well as support for its inclusion from many countries such as the United States.

The assembly meeting followed the recommendation of its General Committee not to allow Taiwan to join as an observer.

The WHO had previously stated on numerous occasions that it lacked the mandate to invite Taiwan, given the disagreement among members over the island's participation in the organization.

In Taiwan on Tuesday, Premier Su Tseng-chang accused China of "obstructing Taiwan's participation based on a political factor."

Su stressed Taiwan's successful effort in containing the virus's spread and said the Chinese opposition represents an "attack" not just on Taiwan but also on the world.

Taiwan's Foreign Ministry said in an earlier statement that it regrets the WHO "continuing to neglect the health and human rights of Taiwan's 23.5 million people."

At Monday's meeting, the Chinese delegate said the issue of "Taiwan region participation must follow the one-China principle."

Taiwan left the United Nations as China joined the world body in 1971. It lost its WHO membership the following year.

Even though the island held observer status at the WHO assembly from 2009 to 2016 as "Chinese Taipei," it has been excluded since 2017 following the election of President Tsai Ing-wen, considered a separatist by mainland China.

The Taiwan issue had been shelved in May as the assembly session was suspended due to the coronavirus pandemic. The session, which resumed in Geneva on Monday, is scheduled to run through Saturday.