White House Chief of Staff John Kelly reportedly “blew up” at President Donald Trump in late March and threatened to resign from his position.

Citing sources familiar with the situation, Axios reported that Kelly lost his temper with Trump during a March 28 meeting in the Oval Office, after which he voiced threats to quit as he walked back to his office.

According to one senior White House official, Kelly was “venting frustration,” and categorizing his comments as a threat was “probably too strong.”

The Hill reported: Sources told Axios that the comments were not related to the firing of Veterans Affairs Secretary David Shulkin, which occurred the same day. Sources also said that other officials, including Homeland Security chief Kirstjen Nielsen, came to calm Kelly down. Kelly also reportedly began packing up personal belongings, according to Axios.

The report comes just days after The Wall Street Journal reported that Trump ignored Kelly’s recommendation to fire Environmental Protection Agency (EPA) chief Scott Pruitt, who has been embroiled in a series of scandals related to spending.

Trump has come to Pruitt’s defense following reports that the EPA administrator stayed in a condo owned by the wife of a lobbyist for well under market value, and that his agency spent millions of taxpayer dollars on a 20-person, full-time security detail.

Trump has in the past reportedly considered firing Kelly and serving as his own chief of staff. It was reported earlier this year that Kelly has frequently threatened to quit as a means of leverage to get Trump to listen to him.