WASHINGTON — President Obama Monday paid a solemn visit to the U.S. Holocaust Memorial Museum, stressing his support for Israel and unveiling new measures to fight oppression.

"We must tell our children about how this evil was allowed to happen because so many people succumbed to their darkest instincts, and because so many others stood silent," Obama told an auditorium filled with survivors, Jewish leaders and human rights activists.

"´Never again´ is a challenge to defend the fundamental right of free people and free nations to exist in peace and security, and that includes the state of Israel," Obama said.

Romanian-American survivor, author and Nobel Prize winner Elie Wiesel led Obama on an hour-long tour of the museum. It was the president´s second trip to the museum, which he said is "a searing occasion whenever you visit."

The two lit candles in remembrance of Nazi victims at the Buchenwald concentration camp, where Wiesel was imprisoned as a teen and where his father perished.

Obama´s great-uncle Charles Payne was among the U.S. soldiers who liberated the camp in April 1945.

Obama Monday leveled new sanctions against "digital guns for hire" who aid the oppressive regimes in Iran and Syria by tracking use of wireless and other technology by dissenters.

"These technologies should be in place to empower citizens, not to repress them," Obama said.

Obama announced establishment of a White House Atrocities Prevention Board, and orders for the intelligence community and the Pentagon to consider genocide risks in assessments and planning.

The President also announced that Jan Karski, a Polish Catholic who alerted the U.S. to Nazi atrocities in his homeland, would posthumously receive the Presidential Medal of Freedom, the nation´s highest civilian honor. (© Copyright 2012 NYDailyNews.com. 04/25/12)