Mitt Romney accused President Obama of Tuesday of adding "insult to injury" with his proposal to raise taxes on families making more than $250,000, calling the move a tax hike on "job creators" at a time of weak economic growth. 

A day after Obama unveiled his tax proposal and urged lawmakers to act, the debate moved quickly to the presidential campaign trail. As Romney hammered the president at a town hall in the battleground state of Colorado, Obama rallied a crowd in Cedar Rapids, Iowa, in support of his plan. 

"To give me another tax break or to give Warren Buffett another tax break or to give Mitt Romney another tax break -- that would cost about a trillion dollars, and we can't afford it, not at a time when we're trying to bring down our deficit," Obama said, adding he's not trying to "punish success." 

The president wants to extend the Bush-era tax rates for everyone making less than $250,000 but let them expire for those making more than that.