Saudi crown prince Mohammed bin Salman has pledged to turn the ultra-conservative Sunni Muslim kingdom into a moderate state, which will be "open to all religions", signalling that sweeping socio-religious reforms will be undertaken.

The powerful heir to the throne said Riyadh will destroy "extremist ideologies" in an attempt to usher in a "more moderate Islam" in the kingdom.

The prince, who will be the next Saudi king, has been credited with some of the major social and economic changes in the kingdom.

The Saudi regime has been rewriting long-established norms in recent months which include lifting of the ban on women driving in the kingdom.

"We are simply reverting to what we followed – a moderate Islam open to the world and all religions. 70% of the Saudis are younger than 30, honestly we won't waste 30 years of our life combating extremist thoughts, we will destroy them now and immediately," he told the Future Investment Initiative Conference in Riyadh on 24 October.

The conference was an international summit to attract investment to the kingdom, which has been attempting to reduce its heavy dependence on oil revenues. His address drew a loud applause from the audience.

"We want to lead normal lives, lives where our religion and our traditions translate into tolerance, so that we coexist with the world and become part of the development of the world," the prince, nicknamed MBS, said. According to analysts, his statement is bound to rile the clerical elite who have held sway in the kingdom for decades.

The 32-year-old royal's statement is seen to be aimed at the country's youth and as a message to the outside world. He has also set the tone for a 15-year reform programme which seeks to overhaul most aspects of life in the kingdom, a regional heavyweight in the Middle East.

During the conference, the prince also unveiled ambitious plans to set up a megacity and a business zone straddling Saudi Arabia, Egypt and Jordan at an estimated cost of $500bn (£381bn).