President Trump took a swipe at a political opponent on Monday during an event at the White House honoring Native American code talkers who assisted the U.S. in concealing communications during World Wars I and II.

"You were here long before any of us were here," Trump told the Native Americans gathered at the White House on Monday.

"Although we have a representative in Congress who they say was here a long time ago," Trump joked. "They call her Pocahontas."

Trump was referring to Sen. Elizabeth Warren, D-Mass., whose critics applied the sobriquet "Fauxcahontas" to her amid a controversy over the ethnicity she once selected on an administrative form.

The president has referred to Warren, a potential 2020 challenger, as "Pocahontas" in the past. Warren responded that Trump "cannot even make it though a ceremony honoring these heroes without having to throw out a racial slur."