KABUL, Afghanistan, Jan. 5 - A suicide bomber blew himself up in a crowd of people on Thursday in the capital of southern Oruzgan Province, killing as many as 10 people, including 2 children, as the American ambassador was meeting with local officials, Afghan officials said.

Up to 50 civilians and police officers were wounded in the blast, in Tirin Kot. The ambassador, Ronald E. Neumann, was not hurt, nor were any of the people traveling with him, said Lou Fintor, a spokesman for the American Embassy.

"The ambassador and his party are safe and have been accounted for," he said. "They were not in any danger."

The ambassador was visiting American troops, part of a provincial reconstruction team based in the city, and was meeting with local officials when the bomb went off.

"The attack does not seem to have been directed at me," Mr. Neumann said in a comment provided by his spokesman.

A Taliban spokesman, Muhammad Yousuf Ahmadi, claimed responsibility for the explosion, naming the bomber and saying that the attack was intended to disrupt the visit by the Americans.

"We knew that there were American officials coming to this gathering but we did not know the U.S. ambassador was attending," he said. The spokesman, reached by telephone, claimed that 15 Afghan and American soldiers were among the casualties. That claim was denied by Afghan officials.

The deputy provincial governor, Hajji Abdul Aziz, said the explosion occurred more than half a mile from the governor's office, where local officials and tribal elders were gathered to meet the ambassador.

Mr. Aziz said the explosion killed civilians in a market, which was busy with shoppers. The provincial security chief, Hajji Ali Ahmad, was among those wounded. Fifteen people were seriously wounded and were taken for medical treatment to the southern city of Kandahar, he said. He said the ambassador left the town 20 minutes after the explosion.

A spokesman for the Interior Ministry in Kabul put the casualties slightly lower than the provincial officials, saying that 8 people had been killed and 35 wounded. He said the bomber blew himself up in a crowd of people watching a dog fight.

Incidents of suicide bombings have increased in the last six months in Afghanistan. Afghans had not usually used this tactic, but there have been about 20 suicide attacks in Afghanistan, most of them in the last few months. Lone bombers have driven explosive-laden cars at American and NATO military convoys, and individuals with explosives strapped to their bodies have thrown themselves at vehicles.

At least four NATO soldiers have been killed in different attacks in the last few months, but often the bombers have failed to hit their target and maimed or killed only Afghan civilians. Thursday's bombing had one of the highest casualty tolls.

Nine people, most of them members of the new Afghan National Army, were killed by a suicide bomber outside their training center in Kabul in September. Nineteen people were killed in a bomb explosion in a mosque in Kandahar in June.

Annotazioni − Ruhullah Khapalwak contributed reporting from Kandahar, Afghanistan, for this article.