Mr. Sessions's statement came hours after Mr. Trump chastised his attorney general's decision to refer a probe of the Justice Department's handling of secret surveillance warrants to the agency's inspector general rather than another office. He said the department "will continue to do its work in a fair and impartial manner according to the law and Constitution".

U.S. Attorney General Jeff Sessions is not exactly the world's most sympathetic figure, but it would take a heart of stone not to feel a slight twinge upon seeing the latest episode in Sessions' co-dependent relationship with his boss, President Donald Trump.

Earlier that morning, Trump had fired off yet another cutting tweet at his beleaguered attorney general, calling Sessions "DISGRACEFUL" for not investigating the F.B.I. more forcefully over its surveillance of the Trump campaign.

On "America's Newsroom" on Thursday, Weekly Standard editor-in-chief Steve Hayes said Sessions "sent a message" to Trump by dining with Deputy Attorney General Rod Rosenstein and Solicitor General Noel Francisco. Trump himself appointed Sessions as the head of the Department of Justice.

White House Press Secretary Sarah Huckabee Sanders said the White House supports efforts to investigate the FISA program, which allows US intelligence and law enforcement officials to obtain secret surveillance orders on Americans suspected of being foreign agents.

For months, Trump has laid into Sessions for not investigating the "crimes" of Clinton, the former Democratic presidential nominee.

Horowitz operates independently within the department.

The report comes as Trump has once again taken to Twitter to criticize Sessions. Not only would Trump struggle to find a replacement who could pass the Senate's muster, but Sessions has signaled on numerous occasions that he will not resign. Isn't the I.G.an Obama guy?

Mr. Sessions rejected the president's attack on Wednesday. Trump has long viewed Sessions' decision to step aside from that investigation as leading to Mueller's appointment.

"Why not use the Department of Justice lawyers?" Sessions was the first sitting senator to endorse Trump, doing so when everyone else thought Sessions was a fool to throw away political capital on a sure loser.

Since then, Mueller's team has been investigating whether the president obstructed justice by firing Comey for failing to stop a federal investigation.

If Trump were to fire Sessions, which seems unlikely, or to eventually push him over the edge into quitting, he probably wouldn't be able to get another attorney general confirmed.

Trump questioned Sessions' commitment to Republican demands that he investigate the use of so-called FISA national security warrants in 2016, when Barack Obama was president, to wiretap members of Trump's election campaign team over their contacts with Russian Federation.

Trump tweeted that "sections of the Wall that California wants built NOW will not be built until the whole Wall is approved".

Special Counsel Robert Mueller is looking into whether Trump's apparent effort to drive Sessions from his job was part of a pattern of attempted obstruction of justice, the Post said, citing people familiar with the matter.

He added, "He was sending a message that everybody knows what's going on here, and so does special counsel".