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 US presidents 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.

The comments from Crown Prince Mohammed bin Salman, reported early Thursday by the state-run Saudi Press Agency, came in a phone call with Trump.

“The crown prince affirmed the kingdom’s intention to broaden its investments and trade with the United States over the next four years, in the amount of $600 billion, and potentially beyond that,” the report said.

The readout did not elaborate on where those investments and trade could be placed. The US in recent years has increasingly pulled away from relying on Saudi oil exports, which once was the bedrock of their relationship for decades. Saudi sovereign wealth funds have taken large stakes in American businesses while also looking at sports as well.

There was no immediate readout from the White House on the call. It also wasn’t immediately clear if Trump’s call with the crown prince was his first with a foreign leader since re-entering the White House. However, it was the first reported abroad.

The crown prince, the de facto ruler of the oil-rich kingdom, also spoke with US Secretary of State Marco Rubio early Thursday.

On Monday after his inauguration, Trump talked about possibly heading to the kingdom again as his first foreign trip, like he did in 2017.

“The first foreign trip typically has been with the UK but ... I did it with Saudi Arabia last time because they agreed to buy $450 billion worth of our products,” Trump told journalists in the Oval Office. “If Saudi Arabia wanted to buy another $450 billion or $500 -- we’ll up it for all the inflation -- I think I’d probably go.”

The 2017 visit to the kingdom set in motion a years-long boycott of Qatar by four Arab nations, including the kingdom.

Trump maintained close relations with Saudi Arabia, even after Prince Mohammed was implicated in the 2018 killing and dismemberment of Washington Post columnist Jamal Khashoggi in Istanbul. The kingdom also had been talking for years with the Biden administration about a wider deal to diplomatically recognize Israel in exchange for US defense protections and other support.