President Hamid Karzai has won a majority of votes in Afghanistan's election, clinching a five-year term and becoming the country's first democratically elected president, according to preliminary results released Sunday.

With 94.3 percent of the votes counted, Karzai was winning 55.3 percent, or 4.2 million, of the votes cast, enough to avoid a runoff, the Joint Electoral Management Body reported. Any showing of less than 50 percent would have required a runoff between the top two vote-getters, according to the Afghan constitution. Even if all the votes that are currently uncounted went to his rivals, Karzai would still win a majority. An official announcement may be made later this week.

Karzai's closest rival, his former education and interior minister, Yonus Qanooni, conceded defeat. Qanooni was far behind with 16.2 percent, or 1.2 million, of the votes cast, the results showed.

Tallying the votes from the Oct. 9 election has been a painstakingly slow process, as election officials said workers needed to become accustomed to the new experience of examining ballots, discerning voter intentions and counting the estimated 8 million votes cast.

Aides to Karzai, the U.S.-backed candidate, have been reluctant to claim victory until a final, official announcement. But the Associated Press quoted a presidential spokesman Sunday night as saying: "We were up against 17 candidates, but the people were behind us. We will sleep soundly tonight."

Qanooni acknowledged his defeat, according to his spokesman, Sayed Hamid Noori, the Reuters news agency reported. The Associated Press quoted one of Qanooni's two running mates, Taj Mohamed Wardak, as saying, "We are waiting for the international experts to decide on the fraud and cheating."

Other Karzai challengers said it was too early to concede before all the ballots were counted and results made official. Along with Qanooni, they had initially announced a boycott of the election, and a refusal to accept the results, because of concerns that voters at some polling stations had washed ink -- intended to prevent them from casting more than one ballot -- off their hands. But the candidates dropped that threat, under intense pressure from U.S. diplomats, and agreed to allow a three-member international panel to investigate whether the ink problem was serious enough to invalidate the results. The panel, consisting of a Canadian, a Briton and a Swede, is due to make a decision in a few days.

The elections body had initially set Oct. 30 as the target date for finishing the vote count and announcing a decision.

While the election was relatively peaceful, despite vows by remnants of the ousted Taliban rulers to disrupt it, the counting was marred Saturday by a suicide bombing on a busy shop-lined street in Kabul that is typically frequented by foreigners. An attacker dressed as a beggar and wearing a string of six grenades detonated the explosives just after 3 p.m., killing himself, a 12-year-old Afghan girl and an American woman, identified as a 23-year-old translator and former Army reservist who lives in Uzbekistan and was visiting Kabul. Apparently three of the grenades exploded, Afghan and foreign officials said.

A purported Taliban spokesman asserted responsibility for the attack in a satellite telephone interview with Reuters in Kabul. Three Icelandic members of the International Security Assistance Force on patrol in the capital were injured in the attack, two slightly and one more seriously. The injuries were reported not to be life-threatening.

A top military official said in an interview that the attacker, whose body was destroyed by the blast, was probably an Afghan, not a foreigner, because he appeared to have a good knowledge of Kabul, and particularly Chicken Street, which is popular with Westerners shopping for carpets and antiques.

Lt. Col. Mohammed Tahir, director of disarmament and demobilization for the Afghan Defense Ministry in the western city of Herat, said remnants of the Taliban may be resorting to suicide bombings because they had been weakened militarily. "The Taliban are getting weaker and weaker, and they know they will soon be finished," he said. "They want to scare people."

"It's like two wrestlers in a match," Tahir said. "The one that is losing decides to throw an illegal punch."

U.N. workers check the validity of voting documents in Kabul, the Afghan capital. About 8 million votes were cast.President Hamid Karzai has received enough votes to avoid a runoff, preliminary results show.