Image caption Top Republican Reince Priebus said the party must adapt to ensure electoral survival

US Republicans have warned they must appeal to minority voters as part of a makeover to counter the party's image as one of "stuffy old men".

Calling November's presidential election defeat a "wake up call", party chairman Reince Priebus said they must also embrace immigration reform.

Republicans are increasingly seen as a party of the rich, he said.

The party has outlined a $10m (£6.6m) plan to reach minority and gay voters in an effort to widen its appeal.

"When Republicans lost in November, it was a wake-up call," Mr Priebus said in prepared remarks posted on the Republican National Committee website.

We should speak out when [chief executives] CEOs receive tens of millions of dollars in retirement packages but middle-class workers have not had a meaningful raise in years Growth and Opportunity Project report

"Our message was weak; our ground game was insufficient; we weren't inclusive; we were behind in both data and digital; our primary and debate process needed improvement," he added.

The 98-page Growth and Opportunity Project report concludes that while Republican principles may be sound, "the way we communicate our principles isn't resonating widely enough".

"Unless changes are made, it will be increasingly difficult for Republicans to win another presidential election in the near future," it concluded.

Mr Priebus, who unveiled the report at an event in Washington on Monday, discussed the stark findings of the report's interviews with some 50,000 people.

"Focus groups described our party as 'narrow minded', 'out of touch', and 'stuffy old men'," he said. "The perception that we're the party of the rich continues to grow."

Among dozens of recommendations, the report also calls for better use of digital technology and databases to engage supporters and raise money - in recognition of President Barack Obama's formidable political machine.

It recommends adopting stricter policies with corporations, loosening campaign finance laws and reducing the number of debates during presidential primaries.

"We should speak out when [chief executives] CEOs receive tens of millions of dollars in retirement packages, but middle-class workers have not had a meaningful raise in years," the report says.

Correspondents say the findings are a recognition that the party must abandon election strategies geared to its base of white male voters. Numbers of US minority voters, who tend to vote heavily Democratic, are growing much more quickly than are those of white Americans.

But the findings may prove unpopular in some branches of the Republican party.

On the issue of immigration reform, political commentator Ann Coulter told the Conservative Political Action Conference over the weekend that Republicans would never win another national election if a path to earned citizenship became law.

But in a speech to the politicians and activists gathered, former presidential nominee Mitt Romney said the party had not lost its way and must remain optimistic.