The Lankan soldiers, who reached the college yesterday for the month-long training, were sent back following the protests, they said.
The soldiers were sent in a bus to Chennai from where they would return to Sri Lanka, the officials said.
Over 200 activists of various pro-Sri Lankan Tamil outfits had staged a demonstration in front of the Madras Regimental Centre (MRC) at Wellington protesting the training programme.
The protesters included members of Periyar Dravida Kazhagam, Naam Tamizhar Party and Viduthualai Chiruthaigal Katchi.
They alleged that Tamils in Sri Lanka were suffering at the hands of that country's Army and the decision to provide training to the island nation's soldiers in Tamil Nadu was condemnable.