Ranchi, Jul 30 (IANS): Both Maoists and Indian authorities have threatened and attacked civil society activists, Human Rights Watch said in a report released Monday.

This has undermined basic freedoms and interfered with aid delivery in embattled areas of central and eastern India, the US-based group said in a 60-page report.

The report documents human rights abuses against activists in Orissa, Jharkhand and Chhattisgarh states.

Human Rights Watch found that grassroots activists who deliver development assistance and publicize abuses in Maoist areas are at particular risk of being targeted by security forces and also Maoist insurgents.

Maoists frequently accuse activists of being "informers" and warn them against implementing government programme.

Police demand that they serve as "informers", and those who refuse risk being accused of being Maoist supporters and subject to arbitrary arrest and torture.

The authorities use sedition laws to curtail free speech and also concoct criminal cases to lock up critics of the government, Human Rights Watch said.

The group called for an immediate end to harassment, attacks and other abuses against activists by government forces and the Maoists.

The report is largely based on more than 60 interviews with residents, activists, journalists and lawyers who were witnesses to or familiar with abuses in the three states from July 2011 to April 2012.