President Barack Obama said accepting immigrants from foreign shores is in America's "DNA," as the nation continued to roil Friday over the arrival of thousands of undocumented minors.

At a Fourth of July event marking the 238th anniversary of American independence, Obama praised the newly minted citizens -- some two dozen active duty military, their spouses, veterans and reservists -- who "remind us that America is and always has been a nation of immigrants."

The president's remarks at the White House came with the country embroiled in a tense debate over how to stanch an influx of undocumented immigrants from Mexico and Central America, among them thousands of minors, who have flooded across the border into the United States in recent months.

"Throughout our history, immigrants have come to our shores in wave after wave, from every corner of the globe. Every one of us -- unless we're Native American -- has an ancestor who was born somewhere else," Obama said.

"That's what makes America special. That's what makes us strong. The basic idea of welcoming immigrants to our shores is central to our way of life, it is in our DNA," the president said.

And he used the event to plug his support for immigration reform, long stalled in the US Congress. 

"We believe our diversity, our differences, when joined together by a common set of ideals, makes us stronger, makes us more creative, makes us different," Obama said.

"If we want to keep attracting the best and brightest from beyond our borders, we're going to have to fix our immigration system, which is broken, and pass commonsense immigration reform," the president added.

"We shouldn't be making it harder for the best and the brightest to come here, and create jobs here, and grow our economy here. We should be making it easier." (AFP)