NEW YORK (CNNMoney.com) -- On the first day of what is to be a two-week economic tour around the country, Barack Obama said Monday that lawmakers should inject another $50 billion immediately into the sluggish U.S. economy.

The presumptive Democratic presidential nominee cited the largest monthly increase in the unemployment rate in over 20 years, and record highs in oil prices, food prices and foreclosures.

"Such relief can't wait until the next president takes office. ... That's why I've called for another round of fiscal stimulus, an immediate $50 billion to help those who've been hit hardest by this economic downturn," Obama told a crowd in Raleigh, N.C.

He said that he supports the expansion and extension of unemployment benefits, as well as a second round of tax rebate checks.

Last week, Democratic leaders on Capitol Hill said that the latest unemployment rate shows that Congress and the Bush administration need to do more to help workers and the unemployed. And they called for a second round of fiscal stimulus.

An economic stimulus package that passed in early February featured tax rebates that are now being sent to more than 130 million Americans. On Friday, the Treasury Department reported that so far it has sent out nearly 67 million stimulus payments worth approximately $57 billion.

Extending unemployment insurance benefits was one measure tossed out of that legislation, but it's considered a leading contender if more stimulus is put in place. One bill, expected to go to the House floor for consideration this week, calls for an additional 13 weeks of benefits to be added to what is typically a 26-week cap on federal payments. In addition, it calls for 13 weeks on top of that for workers in states with very high unemployment rates.

Obama didn't offer details about how much money could go toward rebates and how much would be used to pay for benefits extensions. But the $50 billion in total stimulus that he's calling for represents less than a third of the $170 billion earmarked for the first stimulus package, the bulk of which is being spent on rebates. And the jury is still out on how successful those rebates will be stimulating the economy.

More economic proposals to come

Obama in his speech criticized his Republican rival, John McCain, for proposing to extend all of President Bush's 2001 and 2003 tax cuts.

But Obama himself has taken a page from Bush's playbook on taxes.

Obama has pledged to keep the tax cuts in place for everyone except those making roughly $250,000 and up. He has also made proposals to cut taxes further for the middle class, some of which he reiterated in his speech: exempt seniors making less than $50,000 from having to pay income tax; give a tax credit worth up to $500 per working person ($1,000 per family) to offset the Social Security tax on the first $8,100 of earnings; and expand the earned income tax credit.

To boost retirement savings, he has also proposed a 50% federal match on the first $1,000 of savings for families that earn under $75,000.

Obama said that next week he will lay out his proposals for making the "workforce more competitive by reforming our education system."