U.S. President Donald Trump asked Chinese President Xi Jinping in a letter not to give Iran weapons, and Xi responded that China was not supplying Tehran, the U.S. president told Fox Business Network in an interview that aired on ​Wednesday.

Trump, in the interview taped on Tuesday, did not say ‌when the letters ‌were exchanged. Last week, he threatened countries with an ​immediate 50% tariff if they supplied Iran with weapons.

“I wrote him a letter asking him not to do that, and he wrote me a ⁠letter saying that, essentially, he’s not doing that,” Trump told FBN’s “Mornings with Maria” program. He ⁠also said he did not expect shifts in the global oil market over the war on Iran and changes ​in Venezuela to impact the dynamics ⁠of his planned meeting with Xi next month. “He’s somebody that needs oil. We don’t,” Trump said.