Nato spokesman Brigadier General Josef Blotz said that several arrests had been made in connection with Sunday's blast, the deadliest attack on coalition troops this month.
Sunday's assault in Kandahar came just days ahead of a major White House review of its Afghan strategy following President Barack Obama's decision last year to send 30,000 American reinforcements in an effort to reverse gains by the Taleban since they were ousted in the 2001 US-led invasion.