Saudi Arabia's crown prince said Thursday the kingdom wants to invest $600 billion in the United States over the next four years, comments that came after President Donald Trump earlier put a price tag on returning to the kingdom as his first foreign trip.

Trump's 2017 trip to Saudi Arabia upended a tradition of U.S. presidents first heading to the United Kingdom as their first trip abroad. It also underscored his administration's close ties to the rulers of the oil-rich Gulf states as his eponymous real estate company has pursued deals across the region as well.