A suicide car bomb explosion targeting Afghanistan's energy minister killed four civilians Sunday, while attacks and a violent storm killed six international troops, including three French and two American forces, officials said. Taliban assassination attempts against Afghan officials have intensified this year, with more than 100 officials and pro-government tribal elders attacked - half of them fatally. The convoy carrying Energy Minister Ismail Khan, a powerbroker in the western region of Herat, was headed to the airport when a suicide car bomb exploded outside a high school, said Raouf Ahmadi, a police spokesman. Ahmadi said four civilians died and 17 people were wounded, including four of Khan's bodyguards. He said Khan escaped unharmed and arrived safely at the airport. A Taliban spokesman, Zabiullah Mujahid, claimed responsibility and said the explosion targeted Khan, who was once governor of Herat, a western province bordering Iran. The Taliban assassination campaign is a strong sign of deteriorating security in the country, where a record number of US and NATO troops have also died this year. The Obama administration is now debating whether to send more American troops to Afghanistan as its government faces allegations of widespread fraud from the disputed Aug. 20 presidential election. Two US service members died Saturday in the country's south - one from a roadside bomb explosion and the other from an insurgent attack, the NATO-led force said. A British soldier died Sunday from a bomb explosion while patrolling in southern Afghanistan, Britain's Defense Ministry said. Elsewhere, three French soldiers died in a violent storm in northeastern Afghanistan late Saturday. One soldier was struck by lightning while two were swept away by a rain-swollen river during an operation in Kapisa province, said military spokesman Christophe Prazuck. This year has been the deadliest of the eight-year war for U.S. and NATO troops. The latest six deaths bring to 64 the number of NATO troops killed this month. Elsewhere in western Afghanistan, three Afghan civilians died when their vehicle hit a roadside bomb in Farah province. Gen. Mohammad Faqir Askir, Farah's police chief, said the vehicle had just turned off the main highway toward a village when the bomb exploded. Afghanistan's Interior Ministry said seven Taliban militants were killed in a gunbattle Saturday with police in Kunduz province, once a relatively peaceful region in the north of the country that has recently seen more violence as militants try to expand control.