"Our country is in serious trouble. We don't have victories anymore," he said. "When was the last time anyone saw us beating, let's say, China in a trade deal. They kill us. I beat China all the time."
"When did we beat Japan at anything? They send their cars over by the millions and what do we do?"
The businessman, whom Forbes values at $4.1 billion, said "the United States has become a dumping ground for everybody else's problems."
The 69-year-old is considered a wildcard candidate in an increasingly crowded Republican pool of contenders seeking the presidency in 2016.
Eleven Republicans so far have announced they are running for next November’s election, the latest being former Florida Governor Jeb Bush who launched his candidacy on Monday.
Read more: france 24 - US billionaire Donald Trump announces run for White House - France 24