US Presidential hopeful Barack Obama once again touched on the ticklish issue of outsourcing and while vowing to end tax breaks to companies that ship works overseas conceded that all lost jobs could not be redeemed.

Promising to retain as well as create more jobs for the Americans, the Democratic nominee said while all lost jobs cannot be redeemed, further movement can be halted by giving incentives to companies investing in the country.

"Not all jobs that have left are going to come back. We can stop some of them that are already leaving by stopping to give tax breaks to companies that are shipping jobs overseas and saving those tax breaks for investing in plants and equipment right here in the US," Obama said at a campaign stop in Ohio.

Maintaining that the issues of energy are going to be the "centrepiece of re-building manufacturing in the US", Obama said having energy as one of its main economic planks will ensure creation of millions of jobs as there are growing energy needs in emerging economies like India and China.

Terming the high growth in India and China as a "huge opportunity" for America's energy sector, Obama said the US should choose to invest in clean alternative technologies to milk this opportunity.

"We know that energy is going to be driving the economy in the future. Think about it. China, India -- they are all growing, and they are all deciding we would not mind having a car, too. So as they drive we're already seeing demand outstrip supply in terms of oil," Obama said.

"If we can put research and development into clean coal technology, then we're the Saudi Arabia of coal. And that, right away, helps us and it helps the Ohio economy," Senator

Obama said, adding, "the same is true on nuclear energy".

In his opening remarks Senator Obama had his standard refrain on outsourcing, a theme that he and his campaign have been hammering away in a state like Ohio that has taken a hard hit economically, especially in the manufacturing sector.