By Nandita Bose and Jeff Mason

WASHINGTON (Reuters) -President Joe Biden on Tuesday signed into law the first federal legislation to make lynching a hate crime, addressing a history of racist killings in the United States, after the Senate passed the bill earlier this month.

The law is named for Emmett Till, a 14-year-old Black boy who was brutally murdered in Mississippi in 1955. The bill makes it possible to prosecute as a lynching any conspiracy to commit a hate crime that results in death or serious bodily injury.

Till's death, and an all-white jury's dismissal of charges against two white men who later confessed to his killing, drew national attention to the atrocities and violence that African Americans face in the United States and became a civil rights rallying cry.

With the bill signing, the president was addressing both "unfinished business" and "horror" in America's history, Vice President Kamala Harris said from the White House Rose Garden after the bill signing.

Harris, the country's first Black and Asian American vice president, co-sponsored the bill while serving as a U.S. senator from California.

"Lynching is not a relic of the past. Racial acts of terror still occur in our nation. And when they do, we must all have the courage to name them and hold the perpetrators to account,” she said.

In August, the FBI said the number of hate crimes in the United States had risen the previous year to the highest level in more than a decade, driven by a rise in assaults against Black victims and victims of Asian descent.

Biden, whose support from Black voters helped propel him to the presidency, said the law was not just about addressing crimes of the past.

"It's about the present and our future as well," he said, mentioning a rally of white nationalists in Virginia in 2017. "Racial hate isn't an old problem. It's a persistent problem."

The bill passed the Senate by unanimous consent and the House of Representatives by a vote of 422-3.