(CNN) - American Crossroads, a major conservative super PAC, brought in $5.7 million in June, according to a report the group filed with the Federal Election Commission late Friday.
The organization - co-founded by GOP strategist Karl Rove - has over $31.4 million cash on hand heading into the fall election, the report showed. It spent only $3.7 million last month.
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In June, American Crossroads aired ads in Nebraska, Nevada, and Virginia, the group said.
Several spots tied Democratic candidates for U.S. Senate seats out of those states to President Barack Obama, criticizing them for "wasteful spending," the economic stimulus measure, and for raising the national debt limit.
The group's largest donation - of $2 million - came from Texas homebuilder Bob Perry, who in June also contributed $2 million to the super PAC supporting Mitt Romney, Restore Our Future.
– CNN's Kevin Bohn contributed to this report