(CNN) -- Three coalition service members were killed on Thursday in a blast in southern Afghanistan, the U.S.-led coalition said.
The troops were on a foot patrol when the incident occurred, the coalition said.
The nationalities of the troops were being held until next-of-kin were contacted.
Southern Afghanistan is the center of the Taliban-led insurgency.
More than 3,200 people have died in violence countrywide so far this year, according to an Associated Press tally of figures provided by Afghan and Western officials.
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