Alec Baldwin Gets Into Heated Confrontation with Pro-Palestinian Protester

Alec Baldwin popped up at a pro-Palestinian demonstration in NYC -- and blew a gasket at an anti-Israel protester, prompting police to whisk away the actor before the situation escalated.

Baldwin got into a heated back-and-forth with the man at Monday night's march in Manhattan, which was organized by a Palestinian-led community group, Within Our Lifetime. It wasn't clear if Baldwin was part of the protest or just passing through.

Check out the video shot by NBC ... Baldwin offers a stern look to the man who mentions something about Hollywood -- and condemning Israel for the war in the Gaza Strip.

Baldwin responds, "You've already got your mind made up. I'm in Hollywood?"

The man repeatedly asks, "Is that your answer?"

Baldwin shouts, "You ask stupid questions! Ask me a smart question!"

The man starts screaming again about condemning Israel.

That's when Baldwin completely loses his s**t, getting in the man's face and yelling, "Ask me a smart question!!!!"

Luckily, NYPD officers were right there to escort Baldwin away before things potentially turned violent.

Other videos show Baldwin protected by cops as he gets heckled by protesters who are cursing at him.  At one point, Baldwin turns to the demonstrators and says, "You're really helping your cause."

As you know, Israel has been at war with Hamas since October -- and thousands of people have died on both sides.

Hamas militants -- who govern the Palestinians in the Gaza Strip - triggered the conflict after invading Israel, killing 1,400 citizens.