In his weekly address to the nation Barack Obama discussed the recently signed deal between the US and Afghanistan. Reuters

Barack Obama has declared that his goal of defeating al-Qaida is within reach and that the withdrawal of US forces from Afghanistan would free up money to help rebuild the US economy.

The US president said on Saturday that it was time to focus on domestic concerns, such as helping the middle class who have been squeezed by the economic downturn.

Four days after he visited Afghanistan, Obama said that money saved from ending wars should be used to reduce the country's debt and to boost healthcare, education and infrastructure.

"The tide of war has turned in Afghanistan," he said in his weekly radio and internet address. "We've broken the Taliban's momentum. We've built strong Afghan security forces. We've devastated al-Qaida's leadership. And one year ago our troops launched the operation that killed Osama bin Laden. The goal that I set to defeat al-Qaida and deny it a chance to rebuild is within reach.

"After more than a decade of war, it is time to focus on nation-building here at home."

He said the country should concentrate on economic issues, such as tax disparities and targeted government spending.

Without mentioning the Republicans, he cast the party's view as one that promotes more tax cuts for millionaires while reducing the spending "that built a strong middle class".

"That's why I've called on Congress to take the money we're no longer spending at war, use half of it to pay down our debt and use the other half to rebuild America," he said.

The partisan subtext of the address was clear. Ahead of the presidential election, Obama is portraying the Republicans as the party of the wealthy, while emphasising his efforts to help middle and lower income voters affected by the sluggish economic recovery.

The address came as Obama began his first official presidential campaign trip, visiting college campuses in Ohio and Virginia.

In the Republican address, senator Bob Corker accused the administration and the Senate's Democratic leadership of fiscal mismanagement, saying they had put off difficult decisions that would tame government spending.

"The president punts on almost every tough decision," Corker said.

The Senate's failure to adopt a budget had helped create an atmosphere of uncertainty that was hurting businesses and impeding job creation, the Tennessee Republican said.

He called for an overhaul of the tax code that eliminates most of the $1.2tn in loopholes and tax breaks, lowers rates and broadens the tax base.