Presidents, prime ministers and business leaders have been arriving in Saudi Arabia for “Davos in the desert”, a year after the global elite boycotted the kingdom’s investment summit following the murder of the journalist Jamal Khashoggi.

Brazil’s Jair Bolsonaro, India’s Narendra Modi, King Abdullah II of Jordan and four African leaders are among 6,000 people from 30 countries attending the three-day summit in Riyadh hosted by the Saudi crown prince, Mohammed bin Salman.

Donald Trump’s son-in-law and senior adviser Jared Kushner is among a large US contingent including the treasury secretary, Steven Mnuchin, and the energy secretary, Rick Perry.

David Cameron is due to speak on a panel alongside fellow former prime ministers François Fillon of France, Matteo Renzi of Italy and Kevin Rudd of Australia.

Several business leaders who pulled out of the 2018 summit at the last minute because of public pressure are returning this year. They include Noel Quinn, the interim boss of HSBC; Stephen Schwarzman, the chief executive of the asset manager Blackstone; Larry Fink, the chief executive of BlackRock; and Tidjane Thiam, the chief executive of Credit Suisse.

The murder of Khashoggi, a Washington Post columnist, triggered Saudi Arabia’s biggest diplomatic crisis since the 9/11 attacks as world leaders and business executives sought to distance themselves from Riyadh.

The CIA concluded that Prince Mohammed ordered Khashoggi’s assassination, according to a report by the Washington Post. The crown prince denies involvement, but told US TV last month that he took “full responsibility as a leader in Saudi Arabia”.

The Indian billionaire Mukesh Ambani told the conference on Monday: “I have been coming to Saudi Arabia for 20 years but what I have been seeing particularly in the past two or three years is [economic] transformation. As a businessman and as an investor, I’m all in.”

The South African golfer Ernie Els, the former Nasa astronaut Terry Virts Jr and the rapper will.i.am are also on the list of attendees published by the US news website Axios.