Trump did not say when he made those remarks to the Saudi monarch.
Trump made an undiplomatic remark about close ally Saudi Arabia on Tuesday, saying he warned Saudi Arabia's King Salman he would not last in power "for two weeks" without the backing of the US military.
-Saudi Arabia appears to be bowing again to pressure from Trump.
No further developments have surfaced from the Kuwait meeting but media reports said the Gulf crisis was also on the agenda of the talks.
But oil prices seem to be getting in the way, especially as benchmark Brent crude oil is near $85 a barrel - a four-year high.
The call grabbed the attention of oil traders and hedge funds, who are watching closely for any signs that the USA might take action against Saudi Arabia or other members of OPEC after Trump used his address at the United Nations General Assembly in NY on September 25 to hammer home those views.
Theresa May grooves to ABBA's 'Dancing Queen' at Tory Conference
Prior to beginning her speech, May jokingly asked the audience to "excuse" her if she begins coughing during her address. It's not the first time she's tried to poke fun at her own dance moves, either.
However, the downside of keeping the strategy secret is that if the oil market doesn't know about it, or the fact that Saudi Arabia and Russian Federation chose to ramp up production, then the effect on prices is muted.
The average cost of a gallon (3.78 litres) of petrol in the USA was $3 in May, according to AP.
The Trump administration has had a close relationship with Saudi Arabia.
Qatar has denied the allegations. "We defend many of these nations for nothing, and then they take advantage of us by giving us high oil prices".
"When you have wealthy countries like Saudi Arabia, like Japan, like South Korea, why are we subsidising their military?" asked Trump, who pushes an aggressive "America first" policy on trade.
Oil prices have risen in recent weeks ahead of USA sanctions on Iran - set to be imposed early next month.
Qatar hosts the largest United States military base in the region. South Korea and Japan also have the U.S. to thank for stability in the Asian region, according to Trump, who previously demanded increased payments from USA allies to keep American bases in their countries.