WASHINGTON (CNN) -- A liberal political advocacy group will launch simultaneous television ads in Iowa and New Hampshire next week criticizing Sen. John McCain, R-Arizona, for his call to increase the number of U.S. troops in Iraq.

MoveOn.org will spend more than $100,000 on the ads, MoveOn.org Political Action Executive Director Eli Pariser told CNN in an interview. McCain is seriously considering a run for the 2008 Republican presidential nomination.

In a prime-time address to the nation Wednesday, President Bush will call for sending an additional 21,000 to 24,000 U.S. troops into Iraq.

"We are going to do significant buys in New Hampshire and Iowa with an ad that takes McCain on, on his escalation plan," Pariser said. "Because this is ultimately his idea that Bush is implementing and primary voters need to know that."

Pariser would not specifically comment on the content of the ad, but said it would be released next Tuesday with the initial airing beginning later that week.

A McCain spokesman declined comment on the group's plan to target the senator.