(CNN) – Speaking at the United States Holocaust Museum, President Obama announced on Monday he will award a posthumous Presidential Medal of Freedom to Jan Karski, the former Polish officer who escaped Nazi imprisonment and provided first-hand accounts to the Western Allies of atrocities he witnessed in Warsaw.

“We must tell our children about how this evil was allowed to happen—because so many people succumbed to their darkest instincts; because so many others stood silent. But let us also tell our children about the Righteous Among the Nations. Among them was Jan Karski—a young Polish Catholic—who witnessed Jews being put on cattle cars, who saw the killings, and who told the truth, all the way to President Roosevelt himself,” Obama said in remarks observing Holocaust Remembrance day.

Karski, who later immigrated to the United States and earned a Ph.D from Georgetown University, died in 2000.

The Medal of Freedom is the highest honor a president can bestow on a civilian and is awarded to individuals “who have made especially meritorious contributions to the security or national interests of the United States, to world peace, or to cultural or other significant public or private endeavors,” according to the White House.



Last week, the White House announced it will also award the Medal of Freedom to former Tennessee women's basketball coach Pat Summit. Summit retired from her post this month after 38 seasons because she was diagnosed with early-onset Alzheimer’s disease.

Other 2012 Medal of Freedom recipients will be announced later this year.