The assailant drove a vehicle packed with explosives into the foreign patrol as they drove through Daman district in Kandahar province yesterday.
All three casualties were Romanian soldiers, NATO's Resolute Support train and assist mission said in a statement.
In a WhatsApp message sent to journalists yesterday Taliban spokesman Qari Yousuf Ahmadi said "seven invading forces" were killed in the attack. The militants routinely exaggerate battlefield claims.
The Taliban's latest assault follows the group's pledge to turn Afghanistan into a "graveyard" for foreign forces after US President Donald Trump's announcement last month to keep American boots on the ground indefinitely.
Earlier this month two Taliban suicide bombers launched separate attacks around Bagram Airfield, America's largest base in the country, that wounded several US soldiers and civilians.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)