A suicide car bomber killed three Afghan civilians in Afghanistan's capital Tuesday, while four U.S. soldiers died during fighting in a northern province.
An Afghan police official said the attacker in Kabul struck a NATO convoy outside the military base at the international airport.
The Taliban claimed responsibility for the blast, which wounded another six Afghan civilians and three international soldiers - two Americans and a Belgian.
Also Tuesday, the U.S. military said four U.S. troops were killed while fighting insurgents in northeastern Kunar province. The French news agency said 10 Afghan soldiers also died in the clash.
Meanwhile, NATO acknowledged for the first time that Afghan civilians were killed in last Friday's air strike on two fuel tankers in northern Kunduz province and ordered a full investigation.
The commander of NATO's force in Afghanistan, U.S. General Stanley McChrystal, named a Canadian officer, Major General C.S. Sullivan, to lead the inquiry.
German commanders ordered the air strike, saying it was aimed at Taliban insurgents who had hijacked the two fuel trucks.
Speaking in parliament in Berlin Tuesday, German Chancellor Angela Merkel expressed regret for any civilian deaths, saying any innocent person killed in Afghanistan is "one too many." She also called for patience to determine precisely what happened, and defended Germany's military mission in Afghanistan.
German Defense Minister Franz Josef Jung said the tankers could have been used in a major attack on German soldiers based nearby.
Local officials and human rights workers said up to 70 civilians died when the fuel tankers exploded. Military officials have said they believed they were targeting a group of 120 Taliban.
Some information for this report was provided by AFP, AP and Reuters.