Undocumented immigrant activists in San Francisco came face to face with U.S. Homeland Security officials on Thursday night when, as part of a protest against deportations, they blocked a bus that was carrying foreign nationals who were in the custody of immigration officials.

The activists shouted “Undocumented, unafraid!” as they surrounded the bus, keeping it from moving forward, according to the San Francisco Bay Guardian.

They taped a hot pink sign onto the bus that said: “Shut Down ICE,” the acronym for Immigration and Customs Enforcement, the division that handles deportations.

Homeland Security officials confronted the activists and threatened to press felony charges against them if they did not move and let the bus could pass. The activists decided to continue their protest, the newspaper said. Several were detained by local police and later released.

Dean Santos, a California immigrant who took part in the Thursday protest in San Francisco, defended surrounding the bus to push for an end to the record deportations.

“I’ve been in that bus before, and I remember how powerless I felt,” said Santos, who in the past faced deportation and was held in a detention center in Arizona, according to the website notonemoredeportation.com “Now, I’m coming back with the power of our communities in our effort to stop the separation of families.”

The confrontational action was the latest in a flurry of protests that have employed provocative tactics to jolt lawmakers in Washington D.C. to get back to work on passing an immigration reform bill that would, among other things, provide a path to legal status for many of the nation’s estimated 11 million undocumented immigrants. 

And they’ve directed many of the more recent protests at President Obama, under whom a record number of deportations – nearly 2 million – have taken place during his time in the Oval Office. Some call Obama the Deporter-In-Chief.

The activists, and the organizations that helped coordinate the actions, say that protests will be more frequent and more in-your-face.

“You’ll see more people doing more to do what the president should’ve already done by now — stop deportations,” said B. Loewe, the communications director for the National Day Laborer Organizing Network, to Fox News Latino on Friday.

Several of the long established immigration advocacy groups said this week that while they sympathize with the reasons behind the other groups’ dramatic tactics, they will not be following suit. But on Friday, some established groups that have traditionally relied on diplomatic efforts to influence immigration reform in Washington D.C. say they, too, are ready to turn to more dramatic tactics to pressure both Democrats and Republicans to address the issue.

“What some observers don’t get is that the push for immigration reform is not just a legislative campaign but a movement for change,” said Frank Sharry, who heads America’s Voice, a Washington D.C.-based organization that favors more flexible immigration laws, and a path to legal status for undocumented immigrants. 

“Of course, advocates and activists want Congress to act, but if they don’t, we won’t go away,” Sharry said. “We’ll get louder, stronger and more confrontational. That’s what movements have always done.  And that’s what our movement is already doing.”

Both the more radical and the more traditional immigration advocacy groups say they are frustrated by the inaction in Congress on immigration reform, which earlier this year seemed promising.

In June, the Senate passed a bipartisan comprehensive bill that, at its core, would tighten border security, interior enforcement, but also provide a way for undocumented immigrants to legalize their status. But the effort has stalled in the GOP-controlled House of Representatives, where a conservative faction of lawmakers has vowed not to approve any measure that gives “amnesty” to undocumented immigrants.

Many proponents of strict immigration enforcement have expressed outrage over the increasingly provocative protests of recent weeks, seeing them as a kind of anarchy.

They say that people who are in the United States illegally have no moral authority to make demands and create disruptions by blocking streets and forcing police to be pulled from their regular patrols to deal with protesters.

Following the deal in Congress that ended the partial government shutdown, Obama vowed that attention would return to issues such as immigration. But many activists for immigration reform say they have heard him say that too many times before, and they feel they have no choice but to keep pressing.

In recent weeks, undocumented immigrants and their supporters have handcuffed themselves to the White House fence, chained themselves to tires of buses carrying immigration detainees who are slated for deportation, and chained themselves outside a federal courthouse, forcing a judge to cancel deportation proceedings.

Activists have had tense moments with police. In Tucson, police officers pepper-sprayed members of a crowd trying to prevent U.S. Border Patrol agents from detaining two people who originally police encountered during a traffic stop.

The Tucson Police Department dispatched 100 officers to deal with protests at two locations, something that Sgt. Chris Wildmer told reporters entailed pulling them off patrols throughout the city.

Kica Matos, director of Immigrant Rights and Racial Justice at the Center for Community Change, one of the more prominent, long-established advocacy groups, said on Friday that the time has come to get louder and bolder.

“These and other actions [are] aimed at escalating in a way that communicates to our legislators the despair and sense of urgency that families are feeling,” she said. “One the one hand, the enforcement machinery is working overtime to deport literally thousands of people every week; on the other hand, our legislators just can’t seem to get it together enough to pass a bill that is long overdue.”

“Families are frightened, angry and more resolute than ever to escalate their actions until we have reform,” she said. “Until then, we will see more acts of civil disobedience all around the country.”

Elizabeth Llorente can be reached elizabeth.llorente@foxnewslatino.com