By ZEKE MILLER and ALEXANDRA JAFFE Associated Press

WASHINGTON (AP) — President Joe Biden is calling some Republican governors "cavalier" for resisting his call for far-ranging new federal vaccine requirements he hopes will finally contain the surging delta variant.

Biden visited Brookland Middle School on Friday, just a short drive from the White House He was making the case for new federal rules he set out Thursday that could impact 100 million Americans.

Biden also pushed back against Republicans, and some union officials, who have charged that he is overreaching his authority.

Asked about potential legal challenges to the new vaccine requirements, Biden responded, "Have at it."