Yad Vashem extended the invitation after the White House's Press Secretary drew an especially controversial comparison between Syria's Assad and Nazi leader Hitler. Spicer triggered an uproar on Tuesday (April 11) by saying Adolf Hitler did not use chemical weapons. He apologized after his comments drew immediate criticism on social media and elsewhere for overlooking the fact that millions of Jews were killed in Nazi gas chambers. As Spicer told CNN: "It was a mistake. I shouldn't have done it and I won't do it again." A senior member of Israel's government welcomed Spicer's apology on Wednesday.