Amid alarms being sounded about the loss of American jobs to foreign countries, United States President George W Bush on Friday rejected economic isolationism, saying the greatest challenge the country faces is to train its workforce for jobs of the 21st century.

Referring to complaints about outsourcing, he said the US has to make sure that its workforce is changed to meet the needs for the jobs which exist.

"The Workforce Investment Act needs to be reformed in a positive way so that people are trained for jobs which actually exist," he said in Des Moines, the heartland of America's agriculture.

He said there is a lot of talk about economic isolationism in Washington right now. "That means throwing up barriers to trade. I will resist that mightily, because I believe that when you are good at something, you ought to promote it.

"We are really good at growing things, and we ought to be selling things that we grow, everywhere around the world. We are 5 percent of the world's population. Why don't we sell to the other 95 per cent as opposed to walling ourselves off?"

Good economic development policy in rural America depends upon our ability to open up markets for products made in rural America, Bush added.