Attorney General Jeff Sessions in the White House this month.

WASHINGTON — President Trump criticized his own attorney general, Jeff Sessions, on Wednesday and called him “DISGRACEFUL” after Mr. Sessions indicated that the Justice Department’s watchdog would look into accusations of potential abuse of surveillance laws rather than the agency’s own lawyers.

In a 43-word tweet, Mr. Trump scolded the attorney general, belittled the role of the Justice Department’s independent watchdog and pressured the agency to speed up its investigations.

The tweet was the latest example of Mr. Trump publicly excoriating Mr. Sessions and wading into Justice Department investigations. Though previous presidents have allowed law enforcement a large degree of independence to keep from influencing their inquiries, Mr. Trump has consistently called for investigations into his political rivals and he has criticized Mr. Sessions for not being more aggressive.

It was not immediately clear what prompted the president’s outrage over Mr. Sessions, who last year recused himself from the investigation into Russian interference in the 2016 election and possible coordination with Trump associates.

The attorney general, one of Mr. Trump’s earliest supporters in his election campaign, has been a regular target of the president, who has criticized Mr. Sessions for his recusal — the first in a series of steps that led to the appointment of an independent special counsel to handle the ongoing Russia investigation.

Republicans have accused Justice Department and F.B.I. officials of abusing their powers by surveilling a former Trump campaign aide, Carter Page, during the course of an investigation into Russian meddling. As part of that investigation, law enforcement officials were granted permission to spy on Mr. Page from the secretive court that issues…