Former New York Mayor Rudy Giuliani was roundly criticized Monday after claiming that no "radical Islamic terrorist attack" had taken place in America before President Barack Obama took office in 2008.

"Under those eight years before Obama came along, we didn't have any successful radical Islamic terrorist attack in the United States. They all started with (former Secretary of State Hillary) Clinton and Obama got into office," Giuliani told a crowd gathered in Youngstown, Ohio, for a campaign rally for Republican presidential nominee Donald Trump.

Giuliani was serving as New York's mayor on Sept. 11, 2001, when Islamic terrorists backed by al-Qaeda killed nearly 3,000 people during coordinated attacks on the U.S., including ones on the Twin Towers of the World Trade Center in New York.

His claim Monday came just after he called the Sept. 11, 2001, "the worst foreign attack since the War of 1812."

People on social media immediately took Giuliani to task for  his selective memory.