The plan to spur job creation that President Barack Obama is expected to present on Thursday to both houses of Congress includes an injection of about $300 billion into the U.S. economy.

So far, the administration has not confirmed the figures presented in media accounts.

The president's proposals "will be specific, they will be measurable, they will be paid for," White House spokesman Jay Carney said Wednesday at his daily press briefing.

He declined to mention a specific figure.

"The president will propose new meaningful initiatives to create jobs and grow the economy and it will be fully paid for," White House Communications Director Dan Pfeiffer said on Twitter.

The plan will include investments in infrastructure and direct aid to state and municipal governments, according to press stories citing unnamed officials.

It will also include an extension of payroll tax cuts as well as an extension of jobless benefits.

In addition, it will also include tax breaks for companies that hire previously unemployed workers.

To win over the Republicans, who hold a majority in the House of Representatives and have made spending cuts their main electoral issue, Obama, according to the sources, will offer deficit reductions identical in size to the amount of the plan.

With these announcements, the president is seeking to regain the political initiative in the face of a Republican surge in the polls and to give a new boost to the still-stagnant economy, the latest indicators for which have given rise to fears of a double-dip recession.

More than two years have passed since the United States emerged from its worst economic slowdown since the Great Depression, accompanied by the loss of 8.5 million jobs.

The recovery continues to be slow, however, and the unemployment rate remains above 9 percent.

The economic situation is the main concern of voters in the runup to the November 2012 elections and, according to opinion polls, more and more Americans believe the country is moving in the wrong direction.

All that translates into the fact that the president, according to surveys released this week, has fallen to his lowest level of popularity since he took office, around 44 percent, while more than 50 percent of the public is dissatisfied with his handling of the economy.

At the same time, the number of voters who are considering voting Republican is growing.