WASHINGTON (AP) -- President Barack Obama says the contributions Asian-Americans and Pacific Islanders have made to the U.S. underscore the need to overhaul the nation's immigration system.

Obama spoke at a White House event marking Asian-American Pacific Islander Heritage Month. He lauded Asian-Americans and Pacific Islanders for helping build and defend the United States, and he called for immigration laws that would respect that history.

A White House-backed immigration overhaul is working its way through Congress. The bill would remake immigration laws, enhance border security and put the estimated 11 million people living in the U.S. illegally on a path to citizenship.

Obama opened his remarks by pointing out what he called "a sign of warmth" from the audience gathered in the East Room of the White House — a lipstick smear on his collar. He pinned the blame on the aunt of Jessica Sanchez, a runner-up on the talent show "American Idol," who was in the audience.

"I do not want to be in trouble with Michelle," Obama said in a joking reference to the first lady, "so I'm calling you out."