Rep. Steve King, a Republican from Iowa and the House's leading immigration hawk, complained Thursday about young immigrants who had shown up to protest his bill that would defund President Barack Obama's deferred action program.

King wrote on Twitter that "20 brazen self professed illegal aliens have invaded my DC office. Obama's lawless order gives them de facto immunity from U.S. law."

The congressman sponsored a measure to defund Obama's 2012 executive action that gave young unauthorized immigrants relief from deportation and a work permit if they attend or graduate high school and have no criminal record. The amendment to quash the program passed the Republican-controlled House last week, but is all but certain never to make it out of the Senate.

The Senate is currently debating a sweeping immigration reform bill that would legalize millions of immigrants, and the House's vote on deferred action was seen as a parting shot on the issue. King asked two of the main champions of the reform bill—Sen. Chuck Schumer and Sen. John McCain—to "guard" the door to his office in his cantankerous tweets.

One of the leaders of the protest, Julieta Garibay, said the protesters—dressed in caps and gowns and carrying signs that said "future teacher," "future lawyer" and other professions—wanted to remind King that "we are here to contribute to the country we love."

"The House GOP has a choice: Will they stand with Steve King and his push to return to deporting Dreamers, or will they do the right thing and lead on immigration reform for our families?" Garibay said in a statement.