Image caption Voters wait in West Palm Beach on Sunday after an the election office extended early voting

President Barack Obama appears close to victory in Florida, the only state yet to declare a result from Tuesday's US presidential election.

Vote counting continues, but the head of Florida's Democratic Party issued a statement congratulating Mr Obama.

Aides to Mitt Romney were also quoted appearing to concede defeat.

Florida's vote cannot change the overall result, but the slow count has brought back memories of the bitterly contested recount in 2000.

The Sunshine State's famous "hanging chads" sparked a crisis in that year's Bush-Gore election, eventually leading to a Supreme Court ruling that installed George W Bush in the White House.

Ground game praise

As of Thursday evening Mr Obama had a 0.7% lead in Florida - totalling more than 50,000 votes - but some ballots have yet to be counted.

The final result is expected by midday on Saturday, after three counties - Broward, Palm Beach and Duval - finish their tallies.

If the final difference in the number of votes for President Obama and his Republican challenger Mitt Romney is below 0.5%, a recount would be automatically triggered.

The big picture is that we have done this to ourselves John Rodstrom, Broward County mayor

But whatever the outcome, it matters little since the Democratic incumbent decisively won the national vote in the electoral college.

As the counting edged towards its end, party operatives in Florida began to concede the race would go to Mr Obama.

"On behalf of Florida Democrats, I wish President Barack Obama congratulations on his re-election and on winning Florida's 29 electoral votes," Florida Democratic Chair Rod Smith said.

"Florida Democrats ran the strongest, largest ground game this state has ever seen," he said, describing it as "appalling" that the state had been unable to report results two days after the election.

Republican officials also said they expected Mr Obama to eventually be declared the winner.

"We thought based on our polling and range of organisation that we had done what we needed to win," Brett Doster, a Florida adviser for Mr Romney, told the Miami Herald.

"Obviously, we didn't, and for that I and every other operative in Florida has a sick feeling that we left something on the table. I can assure you this won't happen again."

Florida Republican spokesman Brian Burgess told the Associated Press that "given the wave that we saw all over the country, we're glad that we gave them enough of a fight in Florida to prolong the battle here as long as we did".

Obama campaign manager Jim Messina told reporters: "We feel we will be the official winner in Florida later today."

Counties must send preliminary results to the state by midday on Saturday.

Voting problems

Long queues were reported across the fourth most populous US state on Tuesday.

Some voters waited to cast ballots until 01:30 local time the next morning, after Mr Romney had already delivered his concession speech.

Tens of thousands of absentee ballots also arrived on election day.

In Broward County, Democratic Mayor John Rodstrom told the Miami Herald: "The big picture is that we have done this to ourselves," blaming a combination of all sorts of municipal, state and federal elections on one ballot.

"We have these tremendously long ballots now," he said.

The Sunshine State's problems began even before election day, with lengthy queues reported during the early-voting period.

Democrats launched a legal challenge against a Republican-backed measure to limit the period that voters could cast ballots before the election, from 14 days to eight.

They said it was a blatant attempt to suppress Democratic turnout - Florida's African-American voters have tended to cast ballots early in previous elections.

But Governor Rick Scott said the measure, passed by the state's Republican-controlled legislature in 2011, aimed to limit voter fraud.

The early-voting period officially ended last Saturday. Election supervisors in Miami-Dade and other counties did open up voting for several hours on Sunday.

But after being swamped by voters, one polling office in Miami-Dade County temporarily shut its doors. Some in line began to shout: "Let us vote!"

There was also a technical error with an automated phone system that told more than 12,500 voters in another county that the election was on Wednesday.

Florida was not alone in reports of lengthy election day lines. Voters waited for hours in states such as Virginia, New York and Washington DC.