Former Vice President Joe Biden said Thursday is a "Day of shame in Congress," after House Republicans passed a bill that would repeal and replace Obamacare, the signature healthcare law fought for and named after his former boss, former President Barack Obama.

On Twitter, Biden said, "Protections for pre-existing conditions, mental health, maternity care, addiction services — all gone."

He added that millions of Americans "will lose coverage," and is putting his hopes in the Senate to stop the legislation.

"Up to the Senate now. Hoping for courage to return," he tweeted.

Republican leaders in the Senate say they will not vote on the House version of the bill, but rather will write their own legislation, incorporating elements of it.