President Obama, still traveling abroad, responded yesterday to increasing criticism that the stimulus package he pushed through Congress is not working to prevent job losses in a still-struggling economy.

In his weekly radio and Internet address, Obama said the critics — which include many GOP leaders in Congress — have little credibility.

"When we passed this recovery act, there were those who felt that doing nothing was somehow an answer," he said.

"Today, some of those same critics are already judging the effort a failure although they have yet to offer a plausible alternative."

The criticism has intensified as job losses have continued to grow.

In the weekly Republican radio address, House Minority Whip Eric Cantor of Virginia expressed for many members of his party the concerns in stark, partisan language.

"Remember the promises? They promised you that if you paid for their stimulus, jobs would be created immediately," Cantor said. "In fact, they said that unemployment would stay under 8 percent. Yet just months later, they are telling us to brace for unemployment to climb over 10 percent. They promised jobs created. Now they scramble to find a way to play games with government numbers by claiming jobs saved."

To that sentiment, Obama responded that critics need to have patience.

He countered that his administration never promised immediate results but always counseled that recovery would take time.

"As I made clear at the time it was passed, the recovery act was not designed to work in four months — it was designed to work over two years," Obama said, adding later: "This is a plan that will also accelerate greatly throughout the summer and the fall. We must let it work the way it's supposed to, with the understanding that in any recession, unemployment tends to recover more slowly than other measures of economic activity."

The debate is likely to continue when Obama returns from his weeklong trip abroad. Administration officials forecast that the unemployment rate is likely to spike to above 10 percent — a double-digit figure that is sure to generate more criticism.