Mitt Romney's presidential campaign has made its biggest ad buy since the launch of its general election media campaign, buying $3.24 million worth of ads in seven battleground states, according to a GOP media buying source.

The new ad buy begins Wednesday and runs through next Tuesday.

So far the campaign has aired mostly positive ads touting what Romney would do if he is elected.

Here is the breakdown of the buy, according to the ad source:

Colorado: $713,035

Iowa: $385,745

North Carolina: $591,705

New Hampshire: $77,500

Nevada: $227,030

Ohio: $838,455

Virginia $402,267

The campaign last week expanded its list of states in which it was airing ads to include Colorado, New Hampshire and Nevada.

President Barack Obama's campaign has bought an additional $12.8 million for ads running June 14-July 2. The campaign will air a 30 second ad attacking Romney on his Massachusetts record. This bring's the Obama team's June total to $27.6 million.

Last week, Obama's campaign made two separate ad buys totaling $14.8 million in 10 battleground states: Colorado, Florida, Iowa, New Hampshire, New Mexico, North Carolina, Ohio, Pennsylvania and Virginia. It is airing two spots attacking Romney's record as Massachusetts governor and one touting President Obama's economic policies.