WASHINGTON -- President Obama on Monday said his recovery plan was on track, trying to calm Americans unnerved by unemployment rates still rising nearly four months after he signed the biggest economic stimulus in history.

Obama admitted his own dissatisfaction with the progress but said his administration would ramp up stimulus spending in the coming months. The White House acknowledged it has spent only $44 billion, or 5 percent, of the $787 billion stimulus, but that total has always been expected to rise sharply this summer.

"Now we're in a position to really accelerate," Obama said.

He also repeated an earlier promise to create or save 600,000 jobs by the end of the summer.

Neither the acceleration nor the jobs goal are new. Both represent a White House repackaging of promises and projects to blunt criticism that the effects haven't been worth the historic price tag. And the job estimate is so murky it will likely never be verified.

The economy has shed 1.6 million jobs since the stimulus measure was signed in February, overshadowing White House announcements estimating the effort has saved 150,000 jobs. Public opinion of Obama's handling of the economy has declined along with the jobs data.

"At the time, our forecast seemed reasonable," Vice President Joe Biden's top economic adviser, Jared Bernstein, said Monday, explaining that the White House underestimated the scope of the recession. "Now, looking back, it was clearly too optimistic."

By now, according to earlier White House economic models, the nation's unemployment rate should be on the decline. The forecasts used to drum up support for the plan projected today's unemployment would be about 8 percent. Instead, it sits at 9.4 percent, the highest in more than 25 years.

Some analysts believe the White House is still not being realistic, that Obama will be lucky if any real job creation from his recovery effort is seen by the end of the year, let alone the employment explosion he predicts.

"I think these estimates are overly optimistic," said Arpitha Bykere, a senior analyst with RGE Monitor.

Obama spoke Monday about "modest progress" in the economy, citing fewer jobs lost last month than expected. He said he hopes to build on that in the months ahead with stimulus programs.

"We've done more than ever, faster than ever, more responsibly than ever, to get the gears of the economy moving again," he said.

But he acknowledged, "I'm not satisfied. We've got more work to do."

Americans apparently agree. Obama's disapproval rating on the economy has risen from 30 percent in February to 42 percent, according to a Gallup poll completed May 31. Sensing weakness on a signature issue of Obama's presidency, congressional Republicans are renewing their criticisms that the stimulus plan has not shown results, only mounting debt.

"This is President Obama's economy, and his administration must provide results and specifics rather than vague descriptions of success that seem to change by the week," House Republican Whip Eric Cantor of Virginia said. "The administration looks dramatically out of touch as they highlight the creation of temporary summer employment in the face of job losses unseen in decades, record unemployment and massive deficits."

By any measure, spending $44 billion in less than four months -- and with unprecedented openness -- is an uncharacteristic feat in Washington. But the expectations have been even higher.

Several economists said Monday the economy is unlikely to see much boost from the stimulus before next year.

"It takes time to organize projects, to get the bids in, the funds out and the work started," said Nigel Gault, chief U.S. economist at IHS Global Insight.

Obama answered his critics Monday by announcing a list of stimulus projects, including many already previously outlined, saying the work will have a huge affect on the economy this summer.

There is money for expanded health services in local clinics; improvements in national parks and medical centers for veterans; money for police and school jobs; and more than 1,800 public works projects.

Without naming names, Obama shot back at skeptics during the Cabinet meeting.

"Now, I know that there's some who, despite all evidence to the contrary, still don't believe in the necessity and promise of this recovery act."

"And I would suggest to them that they talk to the companies who, because of this plan, scrapped the idea of laying off employees and, in fact, decided to hire employees. Tell that to the Americans who received that unexpected call saying, 'Come back to work."'

--—

Associated Press writers Philip Elliott, Ben Feller and Jeannine Aversa contributed to this story.