(Reuters) -Saudi Arabian Crown Prince Mohammed bin Salman told President Donald Trump that the kingdom wants to put $600 billion into expanded investment and trade with the United States over the next four years, the Saudi State news agency said early on Thursday.

In a phone call between the two leaders, the crown prince said the Trump administration's expected reforms could create "unprecedented economic prosperity", the state news agency reported.

The report said Saudi Arabia wants its investments to capitalize on these conditions. It did not detail the source of the $600 billion, whether it would be public or private spending nor how the money would be deployed.

The investment "could increase further if additional opportunities arise", the agency quoted Bin Salman as telling Trump.

Trump fostered close ties with Gulf states including Saudi Arabia during his first term. The country invested $2 billion in a firm formed by Jared Kushner, Trump's son-in-law and former aide, after Trump left office.

Trump said following his inauguration on Monday that he would consider making Saudi Arabia his first destination for a foreign visit if Riyadh agreed to buy $500 billion worth of American products, similar to what he did in his first term.

"I did it with Saudi Arabia last time because they agreed to buy $450 billion worth of our product. I said I'll do it but you have to buy American product, and they agreed to do that," Trump said, referring to his 2017 visit to the Gulf kingdom.