BEIJING — Xu Jiatun, a senior Communist Party official who opposed the Chinese military’s suppression of the pro-democracy demonstrations around Tiananmen Square in 1989 and fled to the United States the following year, died on June 29 in Chino Hills, Calif. He was 100.

The cause was kidney and heart failure, his family said.

Mr. Xu’s death, like his life, was marked by politics. As punishment for his flight in 1990 he was expelled from the party. His wish to return home was never granted, said his son, Xu Jian, speaking by phone from Los Angeles. Most of Mr. Xu’s family remained in China, including his wife, Gu Yiping.

Photographs on the websites of overseas Chinese news media showed flowers sent by some prominent Chinese political families, including the family of Zhao Ziyang, the liberal former premier and general secretary of the party with whom Mr. Xu was friendly.

But in China, his death was not officially recognized. A death notice was published on the website of Caixin magazine, then taken down.