Tens of thousands of workers and students from the remote northeast region returned home last week from Bangalore, Mumbai and other cities fearing attacks from Muslims in reprisal for recent ethnic clashes in the state of Assam.

The Indian government has said many of the Internet posts, fake video clips and phone messages spreading rumours of plans to target migrants were sent from arch-rival Pakistan.

The Ministry of Communications said late Monday that an order had been issued on August 17 but that "such inflammatory and harmful content continued to appear on the social networking sites".

It added the government was meeting with representatives of the sites to curb the content, and it stressed that "a lot more and quicker action is expected from them to address such a sensitive issue".

Google issued a statement on Tuesday saying any content intended to incite violence was already prohibited on its products, including YouTube videos.

"We understand the gravity of the situation... and continue to work closely with relevant authorities," it said in response to the government's demands.

Officials declined to name which other sites were affected, while Twitter and Facebook were not immediately available for comment.