LISBON, Portugal: Tuvalu Foreign Minister Simon Kofe walked out of the opening cermonies of this week's United Nations Ocean Conference in Portugal.

According to Radio New Zealand, the move came after China blocked the participation of three Taiwanese members sitting with the Tuvalu delegation.

Taiwan, which China claims as its own territory, is not a member of the United Nations, and its citizens are unable to attend UN events as official Taiwanese representatives.

The Pacific island nation, with a population of 12,000 people, has had diplomatic relations with Taiwan since 1979 and is one of 14 countries that continues to have diplomatic relations with Taipei, rather than Beijing.

Taiwan is largely excluded from international organizations that have China as a member.

Taiwan's Foreign Ministry thanked Tuvalu and condemned China, stating, "China's arbitrary pressure on UN member states has only once again revealed its nasty nature."

Meanwhile, Zhao Lijian, Chinese foreign ministry spokesman, reiterated Beijing's stance that Taiwan is part of China.

In a daily media briefing in Beijing, he said, "The Taiwan authorities' attempts to squeeze into the United Nations Conference on the Oceans and the Law of the Sea by engaging in petty maneuvers in the international arena or acting as followers of other countries will only demean themselves."

Last year, Kofe captured the world's attention after he addressed a global climate conference standing ankle deep in the sea to illustrate that Tuvalu was "sinking."

Some 7,000 people, from heads of state to environmental activists, are expected to attend the conference.