President Hamid Karzai's campaign manager claimed victory on Friday in the country's presidential election, saying preliminary results showed there would be no need for a second round run-off, Reuters reported.

"Initial results show that the president has got a majority," Deen Mohammad told Reuters, although he said it was the duty of the election commission to announce the official results.

"We will not got to a second round. We have got a majority."

Mohammad said the estimate of victory was based on reports from nearly 29,000 monitors the campaign had at polling stations throughout the country.

However, a spokesman for his chief rival, Abdullah Abdullah, dismissed the claim.

"It isn't true," said Fazl Sangcharaki. "We also say, 'Maybe we don't need a second round and Abdullah has won.'"

Afghan officials and their U.S. protectors have breathed a sigh of relief after the relatively peaceful presidential election, which Taliban militants failed to disrupt despite sporadic attacks across the country.

Official preliminary results are not due for two weeks, but counting began immediately after polls closed on Thursday, and the 6,200 polling stations are required to post their results as they tabulate them.

Polls conducted before the election showed Karzai in the lead but suggested he might be headed for a run-off against Abdullah, a former foreign minister with strong support in the north.

In Washington, President Barack Obama hailed the conduct of the election and vowed to press on with his strategy, which has involved sending thousands of additional troops to the country.

"We had what appears to be a successful election in Afghanistan, despite the Taliban's efforts to disrupt it," U.S President Barack Obama said from the White House.

"We have to focus on finishing the job in Afghanistan but it is going to take some time."

The election was a test for Obama's new strategy aimed at reversing Taliban gains. U.S. combat casualties have risen amid a U.S. troop buildup and opinion polls have shown weakening American backing for the war.