The 69-year-old business mogul told a gathering in Salt Lake City, Utah on Friday that America has now become a "third world country" as compared to infrastructures in China and Dubai, the United Arab Emirates.
"We have become a third world country, folks!," Trump told supporters at an election rally.
"If you go to places like Dubai, China, you look at the roads, at the rail roads, they have the bullet trains that go 100s of miles an hour. And if you go to New York, they're like 100 years ago," he said.
Trump pledged to change things if he is elected president in the November election.
"We are going to bring wealth back again because our country is a poor country. We have a deficit that you cannot believe. We're sitting on a bubble, very dangerous bubble. We are sitting on a big fat ugly bubble. At some point unless we act quickly and smartly, it is going to explode. You need the right people. We have the wrong people now," he said.
Trump's election campaign in Utah was the first after his victories in three States of Florida, Illinois and North Carolina on Tuesday.
The US presidential primary is due to be held in Utah, Arizona and American Samoa on March 22, which altogether have more than 100 delegates.
Trump now leads the delegate count with 678, followed by Texas Senator Ted Cruz (423) and Ohio Governor John Kasich (143). He needs 1,237 delegates to win the GOP nomination.
Trump, who has never held elected office, is currently leading the race for the Republican presidential nomination. His campaign has been marked by controversial statements, including disparaging remarks about women, Mexican immigrants and Muslims, Press TV reported.
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