Washington, Sep 16 (IANS): Former US Vice President Joe Biden has warned that "hate is on the rise again" in America and called for efforts to fight it.

Biden made the remarks on Sunday when delivering a speech in Birmingham, Alabama to commemorate the 56th anniversary of a deadly bombing at the city's 16th Street Baptist Church, reports Xinhua news agency.

On September 15, 1963, a bomb blast at the church killed four African-American girls during church services, which sparked a national outrage. Three former Ku Klux Klan members were convicted of murder for the bombing.

"Hate is on the rise again, and we're at a defining moment again in American history," Biden, who is also a 2020 Democrat presidential candidate, said.

"Hate only hides. It doesn't go away. If you give it oxygen it comes out from under the rocks."

Biden listed several hate crimes in the past few years, including the 2018 mass shooting at a synagogue in Pittsburgh and the 2017 white supremacist rally in Charlottesville.

"Lynch mobs, arsonists, bomb makers, and lone gunmen ... and as we all now realize, this violence does not live in the past," he said.

"The struggle against hate injustice, and institutional racism must be the unrelenting work of our lives."