NATO officials say a suicide car bombing has struck an international military convoy in western Afghanistan, wounding several foreign troops.

Officials and witnesses say the bomb hit a military vehicle near the western city of Herat Saturday.  

It was not immediately clear how many soldiers were wounded in the blast.

The nationalities of the soldiers have not been released.  

Separately, Afghan officials say gunmen shot and killed two men, including a former bodyguard for President Hamid Karzai, outside a mosque in southern Kandahar province.

Elsewhere, officials say NATO forces killed 19 suspected militants in an overnight operation in central Wardak province.

In a separate development, NATO officials say they have launched an investigation into a recent NATO air strike against Taliban militants, in which Afghan officials say at least 17 civilians were killed.

Officials in Afghanistan's southern Helmand province said Friday that the civilians, including women and children, were killed when a house collapsed on them during Thursday's NATO raid.

It is not clear whether the collapse was caused by the raid or by insurgent action.  

NATO officials confirm they carried out an air strike in the Nad Ali district of Helmand province, but not that civilians were killed as a result of the strike. 

Some information for this report was provided by AFP.