Attacks Kill 18 in Southern Afghanistan KANDAHAR, Afghanistan - A suicide bomber detonated his explosives near a police checkpoint and a bank in southern Afghanistan on Saturday, one of two attacks that killed 18 people over 24 hours. Separately, a NATO service member was killed by insurgents in the country's east, according to a military statement. No group immediately claimed responsibility for any of the attacks, but Taliban fighters have escalated their activity as American-led foreign forces reduce their presence in the country. Javed Faisal, a spokesman for the provincial governor in Kandahar, initially said the suicide bomber was in a car that was being searched by the police, but later said new information indicated that the bomber had been on foot. A branch of the New Kabul Bank, several small shops and vehicles were damaged. A witness, Shah Wali, had just stepped out of a taxi to go to the bank when the attacker struck. "I saw a man and a vehicle on the road, and while I was fixing my shoelaces I heard a loud explosion," Mr. Wali said. I don't know if it was the vehicle which exploded or the man standing there. Mr. Faisal said at least six people died - four civilians, one police officer and one private security guard. Another 24 people were wounded, mostly civilians. Taliban spokesmen did not immediately respond to requests for comment. The militant group is especially strong in southern Afghanistan, which is dominated by the ethnic Pashtuns whose members form the bulk of the insurgency in the country. Another 12 people were killed in an ambush involving a roadside bomb in Sangin district in Helmand Province, also in the south, on Friday evening, said Omer Zwak, a spokesman for the provincial governor. Sangin is the scene of a continuing operation by Afghan forces against the Taliban. Mr. Zwak said that 11 men and one woman died in the attack, and that the vehicle also was hit by several rounds of gunfire. Such attacks typically single out security forces, but, in this case, "The victims are all civilians and had no link with the government," Mr. Zwak said. The NATO service member who died was killed in "a direct fire attack by enemy forces in eastern Afghanistan" on Saturday, according to a statement from the military alliance. The statement did not give any further details on the person killed. Mostly American soldiers operate in eastern Afghanistan.