US President Barack Obama has signed into law the $787 billion economic stimulus package, which according to him would rejuvenate the American economy and create as many as three to four million jobs in the next two years.

Minutes before he put his signature on the 1,534 page American Recovery and Reinvestment Act in Denver, Colorado, Obama said, "We have begun the essential work of keeping the American dream alive."

The stimulus bill was passed last week by the US Congress -- House of Representatives and Senate -- without much support from the opposition Republicans. While no Republican voted in its favour, only three Senators supported the bill in the Senate.

Obama cautioned Americans not to immediately expect miracles with the passage of the bill, as the US has a long way to go in reviving its economy.

"Today does not mark the end of our economic troubles. Nor does it constitute all of what we must do to turn our economy around," he said.

"But it does mark the beginning of the end -- the beginning of what we need to do to create jobs for Americans scrambling in the wake of layoffs; to provide relief for families worried they won't be able to pay next month's bills; and to set our economy on a firmer foundation, paving the way to long-term growth and prosperity," Obama said.

Terming it as the sweeping economic recovery package in the US history, Obama said, "What makes this recovery plan so important is not just that it will create or save three and a half million jobs over the next two years� It's that we are putting Americans to work doing the work that America needs done in critical areas that have been neglected for too long -- work that will bring real and lasting change for generations to come."

The money would be used to not only save and create three to four million jobs, but would also result in mega investment into modern infrastructure projects, funding projects which would help the US become energy independent, education and push more funding into scientific research.

"It will make the most significant investment in America's roads, bridges, mass transit and other infrastructure since the construction of the interstate highway system. It will make investments to foster reform in education, double renewable energy while fostering efficiency in the use of our energy, and improve quality while bringing down costs in healthcare," Obama said.