Afghan officials say Taliban gunmen have shot and killed a tribal elder and his son, who was a former bodyguard for President Hamid Karzai.

The two victims were shot to death as they left Saturday's morning prayers at a mosque in the southern province of Kandahar

Afghanistan President Hamid Karzai (File)

Mr. Karzai condemned the attack as an affront to Islam.

In a separate development, three people were killed in a roadside bomb blast in the eastern province of Paktika.

Also, NATO officials say a suicide car bomber struck an international military convoy in western Afghanistan, wounding at least four foreign troops.

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

NATO officials also 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. 

Some information for this report was provided by AFP, AP and Reuters.