Delhi ( CNN ) An international human rights group is calling for an independent investigation of the killings by police of 20 suspected red sandalwood smugglers in southeastern India . `` There must be a criminal investigation to determine whether the police used excessive force , and whether the killings amount to 'fake encounters , ' or staged extrajudicial executions '' , said Abhirr Vp , of Amnesty International India . `` The police are not above the law , and must not be treated like they are . '' Those responsible should be brought to justice , according to Amnesty . `` Lethal force should not be used except when strictly unavoidable in order to protect life , '' Vp said . A police official , Deputy Inspector General Kantha Rao , declined comment Wednesday , saying an `` investigation is still going on . '' The incident in question took place early Tuesday in India 's southeastern Andhra Pradesh state . Forest officials near the town of Tirupati spotted hundreds of smugglers cutting trees for red sandalwood , Rao said Tuesday . The forest officials , who were unarmed , called for police . `` We saw several trees chopped down , '' Rao said said . `` These guys came prepared and were heavily armed . '' Rao said that the ensuing gun battle lasted more than three hours and 20 smugglers were shot . Many of them came from the neighboring state of Tamil Nadu , he said . Amnesty International said the police were claiming self-defense , alleging the suspects attacked them with stone and axes . `` However , no police official was injured , '' the Amnesty statement said . `` Most of the suspected smugglers were shot in the back . '' According to Amnesty , India 's National Human Rights Commission has said the incident `` involved a serious violation of human rights of the individuals , '' and that `` the opening of firing can not be justified on the ground of self defense since it resulted in the loss of lives of 20 persons . '' The commission has asked senior government and police officials to explain the actions of the police and forest officials within two weeks , Amnesty said . Police said sandalwood smuggling is common in the area . Local media are reporting that politicians from Tamil Nadu have lodged a protest against the Andhra Pradesh government , saying the alleged smugglers were murdered in cold blood . Kunal Sehgal in Delhi contributed to this report .
Amnesty calls for probe of India police shooting of 20 suspected smugglers . Police decline comment , saying `` investigation is still going on '' and no one has been arrested yet.