KABUL, (Reuters) – President Hamid Karzai’s campaign  and chief rival Abdullah Abdullah both said yesterday they had  won Afghanistan’s election, with U.S. officials warning the  candidates to keep a lid on simmering tensions.

Both camps said unofficial counts by campaign workers  showed they had won enough votes from Thursday’s election,  which went ahead despite Taliban threats of violence, to avoid  a potentially destabilising second round of voting in October.

The election is a major test for Karzai after eight years  in office, as well as for U.S. President Barack Obama’s new  regional strategy to defeat the Taliban and stabilise  Afghanistan.

Karzai’s campaign manager, Deen Mohammad, said early  results showed Karzai had won a majority. “We will not get to a  second round,” he told Reuters.

Abdullah, Karzai’s former foreign minister, dismissed the  Karzai camp’s victory claim and said he was on track to win in  the first round after Thursday’s vote, which went ahead despite  sporadic Taliban violence.

“I’m ahead. Initial results from the provinces show that I  have more than 50 percent of the vote,” Abdullah told Reuters.     Official preliminary results are not due for two weeks. Obama, who has sent thousands of additional U.S. troops to  Afghanistan, praised the vote as a move in the right direction.  But he warned that Taliban violence may continue as official  results are finalized.

“Over the last few days, particularly yesterday, we’ve seen  acts of violence and intimidation by the Taliban, and there …  may be more in the days to come,” he said at the White House.

Election observers say a second round between Karzai, an  ethnic Pashtun, and Abdullah, who draws support from Tajiks in  the north, risked dividing the country along ethnic lines, and  that disagreement over the outcome could lead to civil unrest.    U.S. envoy Richard Holbrooke said he was sure the outcome  would be disputed and told candidates to keep a lid on  tensions.

“We always knew it would be a disputed election. I would  not be surprised if you see candidates claiming victory and  fraud in the next few days,” said Holbrooke, who met Karzai and  Abdullah in Kabul yesterday.

Abdullah urged “calmness, patience, a sense of  responsibility” from his supporters. “Violence should be  avoided in any circumstances,” he told Reuters at his home in  Kabul.

Polls conducted before the election showed Karzai in the  lead but suggested he would not gain the outright majority  needed to avoid a run-off.

Afghan and U.S. officials breathed a sigh of relief after  the relatively peaceful election, which had been marked by a  dramatic escalation in violence in the weeks leading up to the  vote.

The 6,200 polling stations are required to make their  results available to the public as they tabulate them to  prevent fraud.