WASHINGTON, D.C. - For the second time in a month, progressive activists disillusioned with the Obama administration's immigration policies intentionally had themselves arrested outside the White House in what they called an act of "civil disobedience."

The highly choreographed sit-in, organized by a coalition of labor, immigration reform and religious groups, featured roughly 100 demonstrators who sat down on the sidewalk outside the president's residence in an area already cordoned off by law enforcement. After several warnings from law enforcement officers on standby, the scores of protesters were peacefully detained for obstructing sidewalk traffic.

The demonstrators are demanding the federal government cease an estimated 1,000 deportations a day of undocumented immigrants, a number likely to rise as the administration grapples with a surge of thousands who have overwhelmed Southwest states in the last several months, creating a humanitarian crisis. The migrants come mostly from Central America, fleeing violence and epidemic poverty.

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Hundreds of their supporters looked on, waving picket signs that read "Don't deport my dad," and, " Immigration reform is obstructed by racism."

A mile away at a pre-rally outside the Immigration and Customs Enforcement agency headquarters, organizers said the undocumented "would have justice."

"Seventeen American citizen children, today, will be losing their moms or dads for a senseless deportation system that ICE does on daily basis," said AFL-CIO executive vice president Tefere Gebre, "The president can and will stop this. Yes, we can!"

Other groups present included CASA de Maryland, the National Organization for Women and the Sisters of Mercy.

Arrests were made by the National Park Service Police, which has jurisdiction over the park land adjacent to the White House compound. Officers were prepared with tents and foldout tables to quickly process those who were arrested.

Staged arrests inside the nation's capital are not an uncommon occurrence and several of the groups present today are veterans of the tactic, used to draw attention to their cause. Typically, detained demonstrators are handed over to the city's metropolitan police force for processing and released after a few hours, with no fine or further punitive action. Even members of the U.S. Congress have been known to participate.

In June, President Obama announced he would exercise his executive authority to circumvent congressional intransigence on long-term immigration reform. Senior officials told ABC News a decision would come by mid-September, but the end result will likely not be as sweeping as many progressive activists have hoped.

Early summer reports suggested the administration was considering measures that would allow millions of the undocumented to remain in the U.S. without deportation. Now, with the fall midterm elections rapidly approaching, red state Democrats fear comprehensive reform could tip a precariously balanced battle for majority control against them, particularly in the Senate.

ABC News' Jeff Zeleny contributed reporting.