“We will not spend the next 30 years of our lives dealing with destructive ideas. We will destroy them today. We will end extremism very soon,” he says.

Saudi Arabia's powerful Crown Prince Mohammed bin Salman on Tuesday vowed to restore “moderate, open” Islam in a kingdom known for its ultra-conservative rule.

“We are returning to what we were before — a country of moderate Islam that is open to all religions and to the world,” he said at an economic forum in Riyadh.

“We will not spend the next 30 years of our lives dealing with destructive ideas. We will destroy them today. We will end extremism very soon,” he said.

He addressed a panel that included business titans Stephen Schwarzman of US private equity firm Blackstone and Masayoshi Son of Japan's technology conglomerate SoftBank.

The panelists later lavished praise on the 32-year-old prince for his "passion", "vision" and "enthusiasm" but he interjected, saying he is only "one of 20 million people. I am nothing without them."

The Crown Prince has announced plans for a new $ 500-billion city to be built in the country's northwest that will be run entirely on alternative energy and be an innovation hub for the future.

The project, dubbed Neom, will be built on untouched land along the country's Red Sea coastline near Egypt and Jordan.

The ambitious project could lead the way in the use of drones, driverless cars and robotics.

The kingdom's sovereign wealth fund, which the crown prince chairs, the Saudi government and global technology firms will help build the city.