US President Barack Obama on Tuesday signed a US$787-billion economic stimulus bill into law in Denver, Colorado, calling it the first step to pave the way to long-term growth.

The sweeping economic rescue package, the American Recovery and Reinvestment Act, is designed to jolt the ailing US economy by providing government spending and tax cuts for both individuals and businesses.

"I don't want to pretend that today marks the end of our economic problems nor does it constitute all of what we have to do to turn the economy around," Obama said before signing the bill.

"But today 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.

"The beginning of what we need to do to provide relief for families worried they won't be able to pay next month's bills.

"The beginning of the first steps to set our economy on a firmer foundation, paving the way to long-term growth and prosperity," the president said.

Obama signed the bill at the Denver Museum of Nature & Science. He will then take a tour of the museum's installation of solar panels, according to a White House press release.

The president is underscoring investments the spending plan will make in the "green" energy-related jobs by signing the bill in Colorado, a state its governor Bill Ritter described on Tuesday as "the home of new energy economy," news reports say.

At the same time, the White House is launching a website at www.recovery.gov, which is supposed to help people find out how federal dollars are being spent, the pace of scheduled construction projects and whether any federal dollars are being wasted.

Since early last week, Obama has turned to appearances throughout the country to sell his economic plans, hoping to sustain support and foster hope among Americans who are giving him high marks in opinion polls.

The public backing for the president's economic plan is in contrast to the partisan atmosphere in Congress, where the stimulus bill was passed last week on votes split mostly along party lines.

Republicans were nearly unanimous in opposing the stimulus bill, arguing that the bill is too wasteful.