President Joe Biden said that signing legislation into law on Thursday establishing June 19 as Juneteenth National Independence Day -- a US federal holiday commemorating the end of slavery in the United States -- will go down as "one of the greatest honors" of his presidency.

"I have to say to you, I've only been president for several months, but I think this will go down, for me, as one of the greatest honors I will have as president," Biden said at the White House during a signing ceremony.

"I regret that my grandchildren aren't here, because this is a really, really, really important moment in our history. By making Juneteenth a federal holiday, all Americans can feel the power of this day and learn from our history -- and celebrate progress and grapple with the distance we've come (and) the distance we have to travel," Biden said.

The ceremony, which took place in the East Room, included some 80 members of Congress -- including members of the Congressional Black Caucus, local elected officials, community leaders and activists. The President specifically noted that Opal Lee, the activist who campaigned to establish Juneteenth as a federal holiday, was in attendance.