India has accused websites in Pakistan of spreading rumors that caused migrants from the country's northeast to flee fearing impending attacks in retaliation for recent ethnic clashes in their home state.

India's Home Minister Sushil Kumar Shinde on Sunday called on the Pakistani government to investigate Indian claims that most of the threatening messages and images had been uploaded in Pakistan.

Last week, railway authorities added extra cars to trains heading to northeastern Assam state to handle the crush of passengers, many of whom were students and workers.

The exodus followed clashes in Assam in recent weeks between ethnic Bodos and Muslims that killed more than 75 people and displaced some 400,000 others.

Animosity and accusations of land-stealing have long simmered in Assam between members of the ethnic Bodo community and the thousands of mostly Bengali Muslim settlers, many of whom came from the former East Pakistan before it became Bangladesh in 1971.