WASHINGTON (AP) — Michelle Obama turned a flag-waving swearing-in ceremony for 50 new American citizens Wednesday into a platform to call for action on the long-bogged-down issue of immigration.

"In many ways, it is because of — not in spite of — our immigrant population that we grow stronger every single day," the first lady told the newest Americans-by-choice.

Fifty people from 44 nations, from Afghanistan to Zimbabwe, took the oath in the historic setting of the National Archives rotunda, where originals of the U.S. Constitution, Declaration of Independence and Bill of Rights are displayed.

The new citizens waved small U.S. flags afterward, and each got a hug from the first lady.

Mrs. Obama was clearly speaking to an audience beyond the rotunda when she told the new citizens that "much of our success is because we still very much are a nation of immigrants." She recited statistics on immigrants who start small businesses, serve in the military and contribute in the arts and sciences.

"Yet today in Washington, folks are still debating whether or not to fix our immigration system even though just about everyone agrees that it is broken," she said.

Mrs. Obama said overhauling immigration policy was the president's legislative priority and that he would keep fighting for it.

President Barack Obama has been pressing House Republicans to act, but they show no appetite to move on legislation to address the millions of immigrants living illegally in the U.S.

The president has been resisting calls from supporters of an immigration overhaul to move ahead unilaterally on the limited changes that he can do on his own.

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(Photo: AP Photo/Susan Walsh)