KABUL (AFP) - A suicide attack near a German diplomatic convoy in Afghanistan's capital Kabul left three Afghan civilians dead Sunday as 20 other people, most of them insurgents, were reported killed in other unrest. There was no immediate claim of responsibility for the suicide bomb, the second in Kabul in three days, but similar ones have been claimed by Taliban-led extremists waging an insurgency. A German FM spokesman in Berlin said a vehicle belonging to its embassy in Kabul had been targeted. "The sole occupant of the vehicle, an Afghan employee of the embassy, was injured," the spokesman said. President Hamid Karzai's office said in a statement three civilians were killed and six wounded in the blast, which it described as a 'barbaric terrorist action'. The attacker was on foot when he blew himself up in front of a boys' high school and about 200 metres from Parliament, police said. It was the second suicide attack in Kabul since Thursday, when a car bomb outside the heavily barricaded US embassy killed four Afghan civilians and wounded nearly 20. The Taliban claimed responsibility for the Thursday blast. Also Sunday, a bomb killed an Afghan guard for the USPI security company in the southern province of Kandahar, provincial government spokesman Zalmai Ayoubi told AFP. Meanwhile, the coalition announced it killed 17 militants as part of its operations helping the Afghan govt fight an insurgency led by Taliban, who were in govt between 1996 and 2001. Sixteen were killed in an operation against a "terrorist network" in Sarobi, about 50 kilometres east of Kabul in an area where 10 French soldiers were killed in an ambush in August. The operation was against a commander of the Hizb-e-Islami faction, led by former Prime Minister Gulbuddin Hekmatyar, said to be involved in kidnappings and bomb attacks. "As coalition forces approached the targeted buildings, 16 armed militants exited the buildings and began manoeuvring on the force. "The militants engaged the force with small-arms fire. The force responded with small-arms fire and precision munitions and killed the militants," it said. Another militant was killed in an operation in the eastern province of Paktia on Saturday and 10 more were arrested, the statement said.