BOSTON (AP) — Democratic U.S. Sen. Elizabeth Warren, an outspoken critic of President Donald Trump, has encouraged graduates of a Massachusetts college to "persist" in the face of "deep challenges."

Warren delivered the commencement address to graduates of Lesley University in Boston Saturday. Warren urged students to "fight for what is decent and just."

The Republican president repeatedly has ridiculed Warren's claims of Native American ancestry, referring to her publicly as "Pocahontas."

The high-profile liberal is often discussed as a potential 2020 election rival to Trump. Warren has said she has no intention of running for president in 2020, but she's also left herself room to reconsider.

She has refused to pledge to complete a second six-year Senate term if she's re-elected in November.