The petition needs at least 100,000 signatures, the minimum threshold to get a response from the White House.
Over 20,000 people have signed an online petition on the White House website seeking help of US President Barack Obama for the release of former Punjab chief minister Beant Singh's assassin Jagtar Singh Hawara.
Sikh hardliners claim to have parallely declared him as head priest or Jathedar of the Akal Takht, the supreme temporal seat of Sikhism in the Golden Temple complex in Amritsar, Punjab.
Launched by US-based separatist group "Sikhs For Justice" (SFJ), the online petition "urges the President to seek release of Jathedar Hawara from India".
Hawara is undergoing "imprisonment till death" for the assassination in 1995 of Beant Singh, the then Chief Minister of Punjab.
The petition needs at least 100,000 signatures, the minimum threshold to get a response from the White House.
"US administration is obligated to intervene in such matters under International Religious Freedom Act of 1998, we are seeking President Obama's support to secure Jathedar Hawara's release who is now supreme religious leader of the Sikh community," said attorney Gurpatwant Singh Pannun, legal advisor to SFJ.
Hawara was chosen by a parallel congregation of hardline groups on November 10 as the jathedar of the Akal Takht, the supreme temporal seat of Sikhism in the Golden Temple complex. This decision does not have the nod of the Sikh Gurudwara Prabandhak Committee, the apex religious body of the Sikhs.