Delhi Police had detained Kashmiri human rights activist Mohammed Ahsan Untoo when he was about to enter Pakistan High Commission on Friday.
Untoo, who runs an organisation International Forum of Justice and Human Rights, had been invited among others, including separatists, from the militancy-hit Jammu and Kashmir by the High Commission to attend the Pakistan Day celebration.
Separatists from the state, including moderate Hurriyat Conference chairperson Mirwaiz Umer Farooq and others, have been staying away from the function for the last three years.
Untoo had recently met jailed Jammu Kashmir Liberation Front (JKLF) leader Yasin Malik at Kot Balwal jail in Jammu. He has been taking up the cases related to alleged human rights violation at the State Human Rights Commission.
The government on Friday decided to boycott the Pakistan National Day event to be held at its high commission here as Kashmiri separatist leaders were also invited.