More than 29 million people in the United States have diabetes, and one in four of these people doesn't know he or she has it, according to a government report released Tuesday.

The figure is up from the previous estimate of 26 million in 2010, the U.S. Centers for Disease Control and Prevention (CDC) said, and it shows that 9.3 percent of Americans, or one in 11, have diabetes.

Another 86 million U.S. adults, more than one in three U.S. adults, have prediabetes, where their blood sugar levels are higher than normal but not high enough to be classified as type 2 diabetes.

The CDC said that without weight loss and moderate physical activity, 15 percent to 30 percent of people with prediabetes will develop type 2 diabetes within five years.

"These new numbers are alarming and underscore the need for an increased focus on reducing the burden of diabetes in our country, " Ann Albright, director of CDC's Division of Diabetes Translation, said in a statement.

"Diabetes is costly in both human and economic terms. It's urgent that we take swift action to effectively treat and prevent this serious disease," Albright said.