WASHINGTON—President Donald Trump expressed his disappointment in Attorney General Jeff Sessions on Tuesday and questioned the importance of Mr. Sessions’s early endorsement of Mr. Trump’s candidacy, but the president declined to say whether he planned to fire him.

“It’s not like a great loyal thing about the endorsement,” Mr. Trump said in an interview with The Wall Street Journal. “I’m very disappointed in Jeff Sessions.”

Asked whether he would remove Mr. Sessions from office, Mr. Trump said he was unhappy with the attorney general’s decision to recuse himself from the probe into Russia’s meddling in the 2016 presidential election.

The president has repeatedly criticized Mr. Sessions in recent interviews and on Twitter.

“I’m just looking at it,” the president said when asked how long he could continue to criticize Mr. Sessions without firing him. “I’ll just see. It’s a very important thing.”