"Revolutions in communications and technology have sent jobs wherever there's an internet connection, that have forced children in Raleigh and Boston to compete for those jobs with children in Bangalore and Beijing," Obama said in a speech in Raleigh, North Carolina.

"We live in a more competitive world, and that is a fact that cannot be reversed," he added. Fresh from his victory over Hillary Clinton to clinch the Democratic party nomination to the White House, Obama said the country must invest in the research and innovation to create jobs and industries.

"I understand that the challenges facing our economy didn't start the day George Bush took office, and they won't end the day he leaves. Some are partly the result of forces that have globalised our economy over the last several decades," he said, kicking off a series of speeches across the country focusing on the economy.

Observing that America's challenges on economic front cannot be overcome by building "protectionist walls", Obama said the country needs to focus on improving plight of the middle-class and investing in education.

"This nation has faced such fundamental change before. And each time, we've kept our economy strong and competitive by making the decision to expand opportunity outward, to grow our middle class, to invest in innovation, and most importantly, to invest in the education and well-being of our workers," the 46-year-old Democrat said.

Obama said the country will have to place a greater emphasis on areas like science and technology that will define the workforce of the 21st century.

"We'll need to invest in the research and innovation necessary to create jobs and industries of the future right here in North Carolina, right here in the US.

"And one place where that investment would make an enormous difference is in a renewable energy policy that ends our addiction on foreign oil, provides real, long-term relief from high gas prices and high fuel costs, and builds a green economy that could create up to five million well-paying jobs that can't be outsourced," the Senator from llinois said.

Obama said the US "can also create millions of new jobs by rebuilding our schools, roads, bridges, and other critical infrastructure that needs repair.

"And because we know that we can't or shouldn't put up walls around our economy, a long-term agenda will also find a way to make trade work for American workers."