The Sri Lankan navy detained six persons on Tuesday and a further seven people on Wednesday, including several children, as more groups of asylum seekers attempted to flee the island.
Both groups attempted to leave the island through Mannar and were apprehended by the Sri Lankan navy, which continues to occupy the region.
"During a special operation mounted by SLNS Thammanna in the North Central Naval Command on 27th September, a group of individuals remaining suspiciously at Sand Banks were approached and interrogated", claimed the Sri Lankan navy.
It went on to claim that the group were “suspected to be remaining there until the arrival of a boat to illegally migrate from the country”.
An almost identical statement was released by the navy the next day as it detained another group at the same location.
The Sri Lanka navy claimed on its website that it "has been conducting regular patrols in island’s waters to thwart all forms of nefarious activities including illegal immigration attempts".
It has stopped several boats of asylum seekers - mainly Tamils from the North-East - in recent months.