Democratic presidential hopeful Hillary Clinton "lacks the mental and physical stamina" to defeat the growing threat of radical Islamic terrorism, Donald Trump said during a national security speech on Monday.

During remarks in Youngstown, Ohio, the Republican nominee slammed Clinton and President Obama for advancing policies that have "unleashed ISIS, destabilized the Middle East and put the nation of Iran in a dominant position of regional power."

While contrasting himself with the former secretary of state, Trump said Clinton is too weak to deal with the Islamic State and the myriad other challenges Americans face.

"[Clinton] lacks the mental and physical stamina to take on ISIS and all of the many adversaries we face — not only in terrorism, but in trade [and] in every other challenge we must confront to turn our country around," he told the crowd.

Clinton challenged questions about her health and physical strength in a podcast last week, saying she tries to "eat right [and] get enough sleep" and participates in yoga, walking and weight-lifting "to keep up" when she is on the campaign trail.