WASHINGTON - US President Barack Obama on Saturday urged Congress to stop the looming sequester that will lead to harmful automatic cuts, and that could threaten thousands of jobs and affect national security.

In his weekly radio and Internet address, Obama warned that the sequester, which will take effect on March 1 if no deal is reached to reduce deficit, will slow the U.S. economy and eliminate good, middle class jobs because of a series of arbitrary, automatic budget cuts.

He also warned that if the sequester comes, it will force thousands of teachers and educators out of jobs, create travel delays across the country's airports and set back medical science for a generation.

Such cuts will also hurt national security by affecting the US ability to respond to threats in the world. For example, the Navy will be forced to delay the deployment of an aircraft carrier to the Persian Gulf. The Pentagon has just announced that if these cuts go through, almost 800,000 defense employees will be forced to take unpaid leave.

But the US president said the sequester can be averted if Congress can pass a balanced plan for deficit reduction.

"They can cut spending in a smart way, and close wasteful tax loopholes for the well-off and well-connected," he said.

The US president criticized Congressional Republicans for refusing to make compromise to allow tax hikes for the wealthiest Americans.

"These are the questions Republicans in Congress need to ask themselves. And I'm hopeful they'll change their minds. Because the American people have worked too hard for too long to see everything they' ve built undone by partisan recklessness in Washington," he said.

The Republicans have insisted for massive cuts in government spending to reduce the spiraling debt rather than increasing taxes for the wealthy Americans, citing this will hinder their ability to make new investments and create new jobs.

In a bid to reach compromise with the Republicans on averting the sequester, Obama on Thursday made phone calls to Republican House Speaker John Boehner and Senate Republican leader Mitch McConnell.

Roughly $85 billion of spending cuts were set to hit various governmental departments this year starting on March 1, a deadline that was agreed by Democrats and Republicans in January to avoid the so-called "fiscal cliff."