Sioux City, Iowa (CNN) - Mitt Romney's campaign is taking aim at rival Newt Gingrich in Iowa mailboxes.
A mailer from the Romney campaign that hit Iowa Republican mailboxes on Thursday highlights a 2008 ad that Gingrich cut with Nancy Pelosi to promote climate change solutions.
"With allies like this, who needs the left?" reads the mailer, which was provided to CNN by a Republican source in Iowa. The mail piece was first reported by the Des Moines Register.
The Gingrich and Pelosi ad campaign was paid for by the Alliance for Climate Protection, a group founded by Al Gore, the former Democratic Vice President turned environmental activist.
Read the mail piece here.
Romney and his campaign have been aggressively criticizing Gingrich over the last week in an effort to undercut his newfound position atop the GOP polls, but the mail piece is the Romney campaign's first paid media attack against the former House Speaker.
Meanwhile, a pro-Romney super PAC called Restore Our Future is spending more than $3 million on television and radio ads supporting Romney and attacking Gingrich.