WASHINGTON — Kevin K. McAleenan, the acting secretary of homeland security, was forced offstage at Georgetown University’s law school by demonstrators who shut down his planned keynote address as they protested the Trump administration’s immigration policies.

Almost immediately after Mr. McAleenan was introduced to give a speech hosted by the Migration Policy Institute, nearly a dozen advocates and law students in the crowd stood up holding signs saying, “Stand with immigrants” and “Hate is not normal.” Standing at the lectern in front of the packed auditorium, Mr. McAleenan tried to start speaking but was drowned out by chants of: “When immigrants are under attack, what do we do? Stand up, fight back.”

The protesters also read the names of the migrants who have died after being detained at the border.

The event was the latest effort by opponents of the administration’s hard-line immigration policies to let their grievances be known to the policymakers carrying them out. Last year, Stephen Miller, one of the chief architects of President Trump’s immigration policies, threw away $80 worth of takeout sushi, fearing that it had been spat on after a Washington bartender screamed at him. Protesters heckled the last confirmed homeland security secretary, Kirstjen Nielsen, last year as she ate at a Mexican restaurant.