Former national security adviser John Bolton reportedly clashed with President Donald Trump about United States sanctions on Iran the day before his ouster.

The president on Monday afternoon said he may lift some sanctions against the country as a way to kickstart nuclear negations with Tehran, a person close to Bolton told NBC News.

Bolton took a hard stance against doing so, the report said.

The following morning, Bolton was out as national security adviser.

Trump, in tweets, said that he had fired Bolton.

“I disagreed strongly with many of his suggestions, as did others in the Administration,” Trump wrote.

But Bolton denied he was axed and said he resigned, tweeting, “I offered to resign last night and President Trump said, ‘Let’s talk about it tomorrow.’ ”

Trump has said he might meet with Iranian President Hassan Rouhani later this month at the United Nations General Assembly in New York.