Karunanidhi recalled that the US Embassy in Sri Lanka had asked Colombo to allow free movement of citizens.
"These family members are calling for information about their missing loved ones. The Embassy calls upon Sri Lankan authorities to allow free movement of these citizens. The right to freely express opinions is universal and protected under Sri Lankan and international law," the US Embassy had said on Wednesday.
Police had allegedly created hurdles to prevent them from proceeding to Colombo and due to the 'anti-democratic' activity, people staged the protest at Vavuniya itself, he said.
"It is condemnable that Sri Lankan government is denying basic democratic rights and is constantly involved in such autocratic activities," he said.