The weakness in U.S. labor markets has gathered extraordinary momentum, wiping away millions of jobs over the past four months alone, the Labor Department reported Friday.

The U.S. economy lost 651,000 jobs in February, the fourth month in a row where job losses were near or above 600,000.

The unemployment rate soared to 8.1% in February, the highest rate in over 25 years.

The economy has lost 4.4 million jobs since the recession began in December 2007, with more than half coming in the last four months. Read full report.

"This is what falling off a cliff looks like," said Lawrence Mishel, president of the Economic Policy Institute.

President Barack Obama called the losses "astounding" and said the figures proved that Washington "did the right thing" by passing the historic $787 billion economic stimulus plan last month.

Obama spoke at a police trainee graduation ceremony in Columbus, Ohio, where the class of recruits had been threatened with layoffs until the stimulus provided the funds to keep them in uniform.