A separate suicide bomber attacked a convoy of NATO and Afghan police in eastern Afghanistan later in the day, killing one civilian, officials said.
The Taliban claimed responsibility for both attacks and said German military personnel in Kabul and other foreign troops in the east were the targets.
U.S. military spokesman Col. Jerry O'Hara said one U.S. service member died from wounds received in the 9:45 a.m. attack on a busy Kabul street. The blast also wounded six American forces and one U.S. civilian, he said.
"They detonated this explosive device right in a crowded area that was both used by civilians and military people," O'Hara said.
Firefighters and soldiers doused burning vehicles in the street near the base with water. Afghan security personnel and U.S. soldiers carried a U.S. service member out of a window near the blast.
Four Afghan civilians died in the blast and at least 19 wounded were being treated at two hospitals, the interior minister said. Two other wounded civilians were at other hospitals, said Gen. Mohammad Zahir Azimi, the Defense Ministry spokesman.
The German Embassy shares a small, two-lane road with Camp Eggers, a U.S. base that serves as the headquarters for soldiers training Afghan police and army personnel. Dozens of armed Afghan security personnel guard the street, and blast walls of concrete and sand-filled mesh-wire boxes line the road.
"It did not breach the wall (of the base)," said Lt. Col. Chris Kubik, a U.S. military spokesman. "It was fairly close but I can't tell you if they were targeting us or not."
A spokesman for the German Foreign Ministry in Berlin said "some personnel" were wounded in the blast, but he did not give numbers. He said they had no reports of deaths.
Windows inside the German compound shattered in the explosion, but the wall protecting the compound is still intact, he said. The spokesman refused to give his name for publication, citing government policy.
A Taliban spokesman, Zabiullah Mujahid, said a Taliban suicide bomber named Shumse Rehman carried out the attack in a Toyota Corolla. He said the bomber targeted two vehicles believed to be carrying German military officers..
"The Germans have forces in the north of Afghanistan and they are involved in the killing of innocent Afghans. The Taliban will target all those countries who have forces in Afghanistan," he said.
Mujahid said the Taliban had been monitoring the movements of German vehicles and planned the attack to target officers believed to be inside.
German Foreign Minister Frank-Walter Steinmeier condemned "this cowardly act of barbarity."
"Germany stands by its commitment in Afghanistan," Steinmeier said in a statement. "We will not let terror deter us from continuing our aid to the Afghan people."
Afghan President Hamid Karzai also condemned the attack and offered condolences to the victims' families.
"These kind of un-Islamic and inhumane acts will only increase people's hatred for the terrorists," Karzai said.
In Saturday's second attack, a suicide bomber in a minivan charged a convoy of NATO troops and Afghan police in eastern Nangarhar province. The explosion in Chaparhar district killed one civilian and wounded three others, said Ghafor Khan, a spokesman for the provincial police chief. He said three police were also wounded.
Mujahid said the bombing was aimed at the foreign military forces in the convoy.
A spokesman for NATO forces, Sgt. Brian Jones, confirmed the bomb attack on the convoy. He said no NATO troops were killed or wounded.
Germany has 3,200 troops in Afghanistan, mainly in the country's north. That region is considerably more peaceful than the country's east or south, but German troops still suffer from occasional bomb attacks.
The U.S. has some 32,000 troops in Afghanistan and plans to send up to 30,000 more this year.
