Online giants Google and Facebook said Monday they had removed allegedly offensive content on their Indian sites as part of a court case seen as a test for Internet control and censorship.

They have been named alongside another 19 Internet firms in private criminal and civil cases being heard in a New Delhi court which will determine whether they can be held responsible for obscene material generated online by users.

In submissions to court Google and Facebook said they had removed the content submitted as part of evidence against them, which is believed to involve obscene images of religious figures and senior Indian politicians.

"This step is in accordance with Google's policy of responding to court orders," Paroma Roy Chowdhury, Google's spokeswoman in India, told AFP.

The groups, including Yahoo! and Microsoft, have appealed to the Delhi High Court asking for the case to be quashed on the basis that they cannot be held responsible for the actions of users of their platforms.

A judge hearing the case in the High Court warned last month that unless the groups cooperated and take steps to eliminate "offensive and objectionable" content they could be blocked "like in China".

Communications Minister Kapil Sibal in December pledged a crackdown on "unacceptable" online content, saying Internet service providers had ignored India's demands to screen images and data before they were uploaded.

Sibal's demands -- reportedly that social networks pre-screen billions of photos, comments and videos posted online -- provoked anger and derision among Indian Internet users.

Experts argued that such demands could not be enforced and smacked of state censorship.