Paul Sancya/AP Photo

More than 25,000 Iowa Democrats caucused Tuesday night in support of President Obama, according to his re-election campaign.

The turnout - touted by Obama's campaign strategists online and on a day-after conference call with reporters - was significant for a candidate running unopposed in the state and signals that the president's grassroots organizing machine hasn't lost its touch of  four years ago.

While only a small fraction of the record 239,000 Iowa Democrats who caucused on Jan. 3, 2008, the showing  for 2012 amounted to roughly one-fifth of all Republicans who huddled across all 99 Iowa counties to pick their nominee the same night.

Obama also enlisted more than 7,500 supporters to join his army of volunteers mobilizing for his re-election, his campaign team said.

Iowa is a "microcosm of what we're building in states across the country," said Obama campaign manager Jim Messina.  "The results showed an incredible amount of enthusiasm for the president's re-election. …  The Republicans should not expect they can build something like this overnight."

The president has campaign offices in every state, with eight in Iowa alone, more than any GOP presidential candidate. He has also won commitments of support from more than 1 million Americans who have donated to his campaign or signed up to volunteer.

Messina said Obama has 71 teams of grassroots neighborhood organizers in Iowa, a mobilization seen in other key battlegrounds as well.  He said the campaign has 62 teams in Michigan and has connected with more than 511,000 voters in Nevada.

The "enthusiasm gap was nowhere to be found last night," he continued, referring to a number of recent polls that have showed Republican voters more excited than Democrats about the November presidential ballot.

A record 125,000 Iowa Republicans turned out to caucus Tuesday.