If the lead holds, Buttigieg would have accomplished a phenomenal feat, having catapulted from little-known mayor with an unusual name to a formidable national figure who would go on to edge out some of the most recognizable names in Democratic politics.

In remarks in Laconia, N.H. after the partial results were released, Buttigieg, the first openly gay man to run for president, choked back tears, seeming to acknowledge the triumph of ascending to this place in a presidential primary without specifically saying so.

His performance, Buttigieg said, "validates for a kid somewhere in a community wondering if he belongs, or she belongs, or they belong, in their own family that if you believe in yourself and your country, there's a lot backing up that belief."

Sanders' campaign released a statement that pointed out his lead in raw votes; under Iowa's caucus system, supporters of lower-performing candidates can switch to a second-choice candidate, a dynamic that favored Buttigieg according to the first batch of numbers. The final alignment of voters determines the allocation of delegates.

"We are gratified that in the partial data released so far it’s clear that in the first and second round more people voted for Bernie than any other candidate in the field," Sanders' statement read.

We want to thank the people of Iowa. We are gratified that in the partial data released so far it’s clear that in the first and second round more people voted for Bernie than any other candidate in the field.”

Still, candidates on Tuesday were reeling over a delay in results out of Iowa, complaining that every hour that passed served to undermine the credibility of the results. A technical snafu had mucked up the system on Monday, leaving candidates to move on to New Hampshire without clarity on who fared well in a first-in-the-nation caucus state that’s traditionally shaped the contours of presidential races.

Speaking to reporters here Tuesday, Iowa Democratic State Party Chair Troy Price would not say when the remaining results would be released.

"A thorough, transparent and independent examination of what occurred yesterday will follow. But let me be clear, my No. 1 priority has been on ensuring the accuracy and integrity of the results,” Price said. “We have been working all night to be in the best position to report results. … The bottom line is that we hit a stumbling block on the back end of the reporting of the data, but the one thing they want you to know is that we know that the data is accurate. And we also have a paper trail and documentation that have been able to use to provide information to help verify the results.”

Trent Spiner and and Quint Forgey contributed to this report.