The world would be a better place if dictators such as Saddam Hussein and Muammar Gaddafi were still in power, top Republican US presidential hopeful Donald Trump said in comments aired Sunday.

The billionaire real estate tycoon also told CNN's "State of the Union" talk show that the Middle East "blew up" around US President Barack Obama and former secretary of state Hillary Clinton, his biggest Democratic rival in the race for the White House.

"People are getting their heads chopped off.

"They're being drowned. Right now it's far worse than ever under Saddam Hussein or Gaddafi," Trump said.