By Chris Mfula and Stella Mapenzauswa
LUSAKA (Reuters) - President Edgar Lungu was ahead of his main rival on Saturday in early counting from Zambia's presidential election, but the main opposition said its count showed their candidate ahead and the vote may have been rigged.
Lungu faces a stiff challenge from United Party for National Development (UPND) leader Hakainde Hichilema, who accuses him of failing to steer the economy out of its slump after Africa's second-largest copper producer was hit by weak commodity prices.
He led with 262,149 votes against Hichilema's 243,794 after 29 of the country's 156 constituencies in Thursday's voting had been collated, the Electoral Commission of Zambia (ECZ) told a news conference also attended by political parties.
Early results announced on Saturday from only eight constituencies had put Hichilema ahead.
In a statement, the UPND said data from its own parallel counting system showed Hichilema beating Lungu "with a clear margin", based on about 80 percent of votes counted.
Electoral officials have warned political parties against making such statements, but all parties have access to the raw voting data and may add up the results faster than the national commission.
The ECZ had hoped to have final results from the elections - in which Zambians also chose members of parliament, mayors and local councillors and decided on proposed constitutional changes - by early Sunday. Results were now expected later, officials said, without giving a time frame.
The commission had earlier rejected UPND charges that some officials were working to manipulate results to the advantage of Lungu's Patriotic Front.
It said police were still investigating a report that an ECZ official had given his identity card on Friday to a man who could then enter the commission's computer room and tamper with the results.
The UPND renewed its calls for the commission to remove some officials from the election process to preserve its credibility.
"There is a syndicate in this institution and the syndicate is colluding to steal the election," UPND lawyer Martha Mushipe said.
LARGE VOTER TURNOUT
The ECZ has also defended the relatively slow pace in announcing election results, saying audits were taking longer than expected due to a large voter turnout.
As of Saturday's count, turnout was at 56.72 percent, far above the 32 percent recorded early last year when Lungu narrowly won an election to fill the vacancy left by the death of then president Michael Sata.
If no candidate manages to win more than 50 percent this time, Zambia will have to hold a second round of elections.
Campaigning for this week's vote centered on the economy, after months of rising unemployment, mine closures, power shortages and soaring food prices.
Supporters of the two main parties clashed in what is generally one of the continent's most stable democracies.
With emotions running high as parties awaited results, the ECZ would need to clearly demonstrate it was acting to resolve complaints to retain the confidence of the electorate, political analyst Lee Habasonda of the University of Zambia said.
"People are giving them the benefit of doubt at this particular time, they have not lost confidence in them yet but yes, there are certain questions being raised about their performance," he told Reuters.
Hichilema says the president has mismanaged the economy but Lungu, whose government has been negotiating a financial support package with the International Monetary Fund, blames weak growth on plunging commodity prices.
(Editing by Tom Heneghan)