President Trump said Wednesday that Hillary Clinton is only worried about North Korea's missile program now, when she should have been worried when she was secretary of State from 2009 to 2013.

"After allowing North Korea to research and build Nukes while Secretary of State (Bill C also), Crooked Hillary now criticizes," Trump tweeted Wednesday morning about his former 2016 presidential election challenger.

After allowing North Korea to research and build Nukes while Secretary of State (Bill C also), Crooked Hillary now criticizes. — Donald J. Trump (@realDonaldTrump) September 20, 2017

Trump addressed the United Nations General Assembly at its meeting Tuesday and threatened to "totally destroy" Kim Jong Un's country. He also called Kim "Rocket Man."

"Big meetings today at the United Nations. So many interesting leaders. America First will MAKE AMERICA GREAT AGAIN!" Trump tweeted Wednesday just before a series of scheduled bilateral meetings with world leaders.

Big meetings today at the United Nations. So many interesting leaders. America First will MAKE AMERICA GREAT AGAIN! — Donald J. Trump (@realDonaldTrump) September 20, 2017

The president also said "the world is noticing" after a Twitter user said Trump was making good on his campaign promises.