President Trump said on Friday that he might revoke the credentials of additional White House reporters if they did not “treat the White House with respect,” lobbing another threat at the news media two days after his administration effectively blacklisted the CNN correspondent Jim Acosta.

Asked how long Mr. Acosta’s pass would be suspended, Mr. Trump replied: “As far as I’m concerned, I haven’t made that decision. But it could be others also.”

The president made his comments while speaking with reporters on the South Lawn before boarding Marine One.

“When you’re in the White House, this is a very sacred place for me, a very special place,” Mr. Trump said as he left Washington for a brief jaunt to Paris. “You have to treat the White House with respect. You have to treat the presidency with respect.”