The former president claimed that the Chinese leader "has no respect for our country anymore," adding that Xi "respected our country so much" during Trump's presidential term.
"China would not be going in, [Chinese] President Xi [Jinping] would not be going into Taiwan, and he's awfully close to wanting to go in because he thinks your leader [Biden] is incompetent," Trump said at a rally in South Carolina.
Tensions over Taiwan significantly increased last August after then-US House Speaker Nancy Pelosi traveled to Taipei despite Beijing's warnings against such a visit. China condemned Pelosi's trip, which it regarded as a gesture of support for separatism, and launched large-scale military exercises in the vicinity of the island.
Taiwan has been governed independently from mainland China since 1949. Beijing views the island as its province, while Taiwan - a territory with its own elected government - maintains that it is an autonomous country but stops short of declaring independence. Beijing opposes any official contacts of foreign states with Taipei and considers Chinese sovereignty over the island indisputable.