"We made it clear that we cannot have any trust and conversation unless we address the Dream Act passed," Pelosi said that she told Trump, adding later that she wants the bill "to be the basis of how we go forward. We have made it clear: We are not giving up our fight to protect America's Dreamers from the cruelty of deportation."
As she concluded her remarks, roughly 40 people rushed the stage and started chanting loudly while Pelosi, her security detail, Lee and Huffman watched. They identified themselves as "undocumented youth" - presumably beneficiaries of the Deferred Action for Childhood Arrivals programme or other Dreamers.
"We are not a bargaining chip!" the protesters chanted, according to local reporters.
"All of us or none of us," they said later.
The protesters demanded "a clean bill" - meaning that the Dream Act would get an up-or-down vote on its own without any language regarding border security attached. They "demanded" that Pelosi show a commitment to protecting "all 11 million" undocumented immigrants believed to be in the country.
"We demand accountability. Democrats are not the resistance of Trump. We are!" they shouted.
One male protest leader then started a call and response with the group, addressing Pelosi directly and pointing his finger at her: "Congresswoman Pelosi! You called this press conference in our name to defend the so-called Dream Act," they said.
"First you said you supported a clean Dream Act. And last week you announced that you had agreed and I quote you, 'To work out a package of border security.' Your words. Or were you misquoted? We cannot say, however, that we are surprised," they added.
They also complained that the Obama Administration had systematically deported hundreds of thousands of people."
"Where was your resistance then?" they asked.
"Okay, you've asked your questions," Pelosi said, cutting in.
But they kept shouting, so she let them continue shouting.
"You've asked some questions. You've asked some questions!" Pelosi shouted.
"Let us speak! Let us speak!" they shouted in reply.
"You have," she said.
After nearly 30 minutes, Pelosi and other invited speakers departed.
The protesters were identified as members of the local chapters of Rise, Faith in Action and the California Youth Immigrant Justice Alliance, according to Pelosi aides.
The activists are among the most progressive and vocal protesters and their tactics are not widely employed at similar events nationwide.
Pelosi is not the first - and likely won't be the last - Democratic official to be confronted by immigration activists.
Several times over the course of his presidency, young immigration rights protesters shouted at President Barack Obama during official events, campaign rallies or campaign fundraisers. Given their distance from the President, he usually succeeded in shouting them down or US Secret Service escorted them from the room.
In this case, Pelosi had to stand by, with cameras rolling, as they continued shouting. Her own official Facebook page had been live-streaming the event and her aides encouraged out-of-town reporters to watch it, but the feed cut out as the protesters persisted.
Speaking with reporters later, Pelosi said the protesters were "completely wrong" to blame Democrats for the nation's current struggles to enact comprehensive immigration reform.
"The Democrats are the ones who stopped their assault on sanctuary cities, stopped the wall, the increased deportations in our last bill that was at the end of April, and we are determined to get Republicans votes to pass the clean Dream Act," she said. "Is it possible to pass a bill without some border security? Well, we'll have to see. We didn't agree to anything in that regard, except to listen and something that deals with technology or something like that - but nothing like a wall."
"I wish they would channel some of that energy into the Republican districts so we can pass the Dream Act," Pelosi added later.
Asked whether the protesters she faced were emblematic of wider Democratic Party concerns about her discussions with Trump, Pelosi said that from a political standpoint, she has no choice.
"Trump has the signature. And basically our conversation with Trump is, we don't want to hear about anything that you may want to do unless we have shared values around the Dreamers. And that's our threshold," she said.
Back in Washington, talks to sort out the specifics of the deal sought by Trump and Democrats are set to begin this week, but senior congressional aides said that they had no details yet on plans to begin the talks or what they would focus on - if they ever commence.
