The University of Missouri named a black interim president on Thursday after the incumbent was forced out amid an escalating race row, as a wave of protests spread to half a dozen US campuses.
President Tim Wolfe resigned this week as protests mounted over his handling of racial slurs aimed at black students, including claims a swastika was drawn with human feces on a dormitory wall.
The events at the Missouri school -- nicknamed Mizzou -- have spawned a wave of student solidarity, with thousands sharing grievances and organising protests under the hashtags #BlackOnCampus and #IStandwithMizzou.
Wolfe hands over to Mike Middleton, a black former civil rights attorney and longtime deputy chancellor of the University of Missouri's main Columbia campus.
"The time has come for us to acknowledge and address our daunting challenges," Middleton was quoted as saying in a university statement.
The Missouri row comes as the United States grapples with a surge in tensions between white police officers and African-Americans, fanned by several cases of police shooting unarmed black citizens.
While the protests have been peaceful, they have raised fears of racially-motivated violence.
Two white 19-year-olds were arrested this week for making online threats against black students at Mizzou. One of them, Hunter Park, appeared in court Thursday and was denied bond, local media reported.
Howard University in the capital Washington, a historically black faculty, stepped up security on campus and at nearby metro stations Thursday, after the FBI warned of a racist social media threat against its students.
"We believe it's a threat that has to be taken seriously and that's what the FBI have been doing," Howard President Wayne Frederick told CNN.
The shooting of an unarmed black teen in Ferguson, Missouri, in August 2014, triggered weeks of sometimes violent unrest, fueled the Black Lives Matter movement and opened a national conversation about racism and police tactics.
At Mizzou, the activist group Concerned Student 1950 -- which refers to the year black students were first admitted to the university -- has been at the forefront of demands for change.
Last weekend, dozens of black players on the university's high-profile football team said they would boycott team activities until Wolfe either stepped down or was removed.
The revolt over racial tensions has resonated on other campuses, including Yale University where hundreds marched this week to demand action over allegations that a fraternity held a party for "white girls only."
Hundreds of students at Ithaca College in upstate New York staged a walkout Wednesday, as a group calling itself People of Color at Ithaca demanded the resignation of its President, Tom Rochon, over his response to claims of racial insensitivity.
Fresh rallies and marches were taking place Thursday at a number of schools, including Syracuse University.
Democratic White House hopeful Bernie Sanders weighed in on the debate Wednesday, tweeting: "I'm listening to the #BlackOnCampus conversation. It's time to address structural racism on college campuses."