"Donald Trump should withdraw and Mike Pence should be our nominee effective immediately," Thune said on Twitter. | Getty No. 3 Senate Republican calls on Trump to withdraw

Sen. John Thune of South Dakota on Saturday became the first Republican leader to abandon Donald Trump, a potentially crippling blow for Trump's support in Congress.

The No. 3 GOP leader and Senate Republicans' top message man, Thune asked for Trump to leave the race after the publication Friday of Trump's 2005 comments demeaning women and making sexually aggressive remarks.


"Donald Trump should withdraw and Mike Pence should be our nominee effective immediately," Thune said on Twitter.

The No. 5 Senate Republican leader, Roy Blunt of Missouri, told The Washington Post on Saturday that he will still vote for Trump. Other GOP leaders in the House and Senate have been harshly critical of Trump over the past 24 hours but have not demanded him step aside.