6:28 PM PT -- George Stephanopoulos tells TMZ in a statement from his rep, "Earlier today, I responded to a question from a passerby. I shouldn't have." An ABC spokesperson tells TMZ, "George expressed his own point of view and not the position of ABC News."

George Stephanopoulos just made a stunning comment on the streets of New York ... telling a pedestrian he doesn't think President Joe Biden can serve another term.

The 'GMA' anchor was out and about Tuesday afternoon on 5th Avenue, wearing workout clothes, when the pedestrian approached him and asked, "Do you think Biden should step down? You've talked to him more than anybody else has lately." George's response -- "I DON'T THINK HE CAN SERVE 4 MORE YEARS."

The pedestrian didn't have his phone pointed at George when the ABC News journalist gave his answer -- the phone was pointed at the sidewalk, but it's clearly George's distinctive voice you're hearing.

George's comment is telling, given he had an exclusive sit-down with the Prez just 4 days ago. George pressed Biden on his mental acuity and his dismal debate performance. Outside the White House bubble, George has spent more one-on-one time with the President than just about anyone.

Stephanopoulos, who has had strong ties to the Democratic Party, has been measured but tough in reporting on the post-debate fallout.

One of the most interesting moments of the interview -- when George asked Biden how he'd feel the day after the election if he lost to Trump. The Prez answered he'd feel ok as long as he gave it his all.

It was a revealing moment, for sure.

Biden has made it clear -- he's going to run and no one's going to stop him. Some members of Congress have asked him to step aside, but a large majority of Dems on The Hill are still supporting him.

Further, during Tuesday's WH press briefing, Press Sec. Karine Jean-Pierre was asked if President Biden would be committed to serving all 4 years if he's reelected ... and she calmly responded, "Yes." POTUS would be 86 at that point.

We reached out to ABC for comment ... so far, no word back.