CEDAR RAPIDS, Iowa-Paul Ryan mentioned the national debt surpassing $16 trillion, calling it "a little bit of a downer."

"We just heard about an hour ago that our government eclipsed the $16 trillion mark in our national debt," Ryan said at a rally with over 800 people here. "This is a serious threat to our economy. Of all the broken promises from President Obama, this is probably the worst one because this debt is threatening jobs today, it is threatening prosperity today and it is guaranteeing that our children and grandchildren get a diminished future."

It appears the U.S. first reached the new $16 trillion debt figure last week, on Aug. 31, according to the Daily Treasury Statement. But the milestone was not realized until Treasury quietly posted it on their website today.

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At last week's Republican National Convention in Tampa, a debt clock hanging in the arena ticked the debt upwards. This afternoon, it surpassed that number and Ryan sarcastically noted the Democrats holding their convention this week in Tampa don't have a debt clock.

"The problem is, the president keeps kicking the can down the road. No leadership on this issue. The Senate hasn't even passed a budget in three years. We have a very clear choice ahead of us," Ryan said.

Iowa Gov. Terry Branstad introduced Ryan and also mentioned the national debt and like Ryan bringing out the sarcasm and saying it's "no coincident it's the same day as their convention begins."