Sen. Carl Levin (D-Mich.) on Wednesday sharply criticized a Democratic super PAC working against Senate Minority Leader Mitch McConnell (R-Ky.), saying its tweets about the race of McConnell's wife, Elaine Chao, are inappropriate.

The group's Twitter account suggested in a tweet this month that Chao's Chinese heritage led McConnell to favor outsourcing to China. It also tweeted old rumors that McConnell is gay.

Levin is the first big-name Democrat to publicly denounce the group -- something Republicans called for after the story broke Tuesday.

Update 4:54 p.m.: Sen. Claire McCaskill (D-Mo.) has joined Levin in denouncing the group: