WASHINGTON (AP) -- Republicans have gained ground on Democrats in registering voters in three battleground states and kept their razor-thin advantage in Iowa - encouraging news for Donald Trump eight weeks before Election Day.

Republicans added hundreds of thousands of voters to the rolls since 2012 in states including Florida and Arizona, and narrowed the gap in North Carolina, according to data compiled by The Associated Press. In Iowa, Republicans prevented Democrats from surpassing them, aided by a court ruling upholding a ban on voting by ex-felons, who often register as Democrats.

As Election Day approaches, voter registration drives are in full swing.

Hillary Clinton's campaign is staging registration rallies and appealing in particular to non-whites and young people, who are more likely to vote early - if they vote at all. Trump is relying mostly on a base of white voters, urging supporters to be vigilant for voter fraud and "rigging."

"The Clinton campaign cannot come close to our output," said Sean Spicer, the Republican National Committee's chief strategist, in a campaign memorandum Monday.

The latest registration numbers aren't an assurance of new voters for Trump. Some changes reflect those who have died and been removed from the list, while others are inactive, not having voted in recent elections. In Florida, newly registered Hispanics are turning against the Republican nominee, stung by his anti-immigrant rhetoric. And Democrats historically have done well in signing up new voters in the final stretch.

But the figures, when available, offer important clues as to how each party stands.

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IOWA

Iowa is a bright spot for Trump among battleground states, with Republicans now holding an edge of 19,000 total registered voters over Democrats, 691,000 to 672,000. While independents are the most numerous at 755,000, much of the state's Republican establishment has rallied around Trump. A state court in June upheld a ban on voting for an estimated 20,000 ex-felons, many of them African-American.

The race is "about even" and "very close," said Gov. Terry Branstad in a recent AP interview. In the run-up to the state's early voting, which begins Sept. 29, the Trump campaign struggled initially in its ground game, leading Branstad to offer advice to the New York billionaire on how to get a leg up: TV advertising, appealing to the state's farmers.

Branstad's son, Eric, is running Trump's campaign in Iowa.

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FLORIDA

Both campaigns have heavily targeted Florida, but Democrats have seen their advantage shrink to 258,000 active voters - down from 535,000 in 2012. Overall, Democrats declined to 4.69 million compared to a 4 percent rise for Republicans to 4.4 million, driven by Republican gains among white voters. Registered "no party" independents jumped 13 percent to 2.9 million.

The state imposed voter restrictions in 2011, including cuts to voter registration and early voting, that have since been softened.

But the picture remains murky.

The Republican advantage is primarily due to declines among previous Democratic voters - deaths, moves out of state and voters removed after being inactive for long periods, as well as switches to the Republican Party.

Democrats are registering more new voters than Republicans. Nearly half of all first-time voters registered since 2013 were non-white, many of them Hispanic.

Since January, of the 121,000 newly registered Hispanics, 42 percent are Democrats and 41 percent are "no party," compared to 16 percent for Republicans. It's a shift from the Jan. 1, 2013 to Aug. 1, 2016 period, when newly registered Hispanics were most likely to pick "no party." Before 2013, Hispanics had more frequently opted to register as Republican, with 39.5 percent of them Democrats, 30.5 percent "no party" and 28.4 percent Republicans.

"There's little question that the rise in Democratic registration of Hispanics in Florida is a reaction to the rise of Donald Trump," said Daniel Smith, a University of Florida professor who analyzes trends.

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NORTH CAROLINA

Democrats hold a clear registration advantage in North Carolina, but the gap has narrowed.

A Republican-controlled legislature in 2013 imposed a voter ID law and curtailed early voting and registration. But a federal appeals court in July invalidated the law as discriminatory against blacks, who are more likely to vote before Election Day.

Democrats hold a lead of about 645,000 voters. That's down from an advantage of 818,000 in 2012.

Despite a registration deficit, Republicans have been successful with voter turnout, currently holding the governorship and both Senate seats. Obama lost the state by 92,000 votes to Mitt Romney.

Election officials predict high overall turnout, spurring an appearance by Clinton in Charlotte last week.

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WEST

In the diversifying West, Democrats regained their edge in Colorado, but face challenges in Nevada and Arizona.

Boosted by rapid Latino growth, Colorado saw an increase in registered Democrats since 2012, compared to a 1.5 percent decline for Republicans. That allowed Colorado Democrats to surpass Republicans earlier this year for the first time in more than 20 years. For 2016, the state will conduct all-mail balloting, believed to slightly favor Democrats.

In Nevada, where Trump is competing hard, Democrats maintained their advantage, but Republicans have narrowed the gap.

And in Arizona, traditionally a Republican state, the picture was mixed. Republicans grew at a faster pace, but the biggest jump was among independents, to 1.4 million. Republicans hold a registration edge of about 159,000, although an influx of Hispanic voters and third-party interest have given Democrats hope.

The state has been receiving national attention with a recent hack of voter registration records.

The Homeland Security Department has suggested federal involvement to protect election integrity. But some conservatives oppose that, citing a risk of Democratic "rigging." For 2016, Arizona placed new limits on mail-in ballot collection, which Democrats are challenging in court as restrictive.

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AP writers Catherine Lucey in Charlotte, N.C., Scott Bauer in Des Moines, Iowa, and AP's Election Research and Quality Control Group contributed to this report.

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