India's prime minister said Friday that the unity of the country was at stake as thousands of migrants from the northeast continued to flee Bangalore and other cities after anonymous threats.
Extra trains were put on for the second night in a row to accommodate panicked students and workers leaving the south and returning to their homes in the northeastern state of Assam.
The exodus has been sparked by threats sent via mobile phones and the Internet that Assamese people would be attacked by Muslims after the end of the holy month of Ramadan next week in reprisal for recent ethnic violence.
Bulk text messages were on Friday temporarily banned to try to halt the spread of threats and incendiary rumours.
Three weeks of clashes in remote Assam between members of the Bodo tribal community and Muslims have claimed 80 lives and displaced more than 400,000 people.
"What is at stake is the unity and integrity of our country. What is at stake is communal harmony," Prime Minister Manmohan Singh told parliament.
"If there are miscreants, if there are people who are fanning these rumours, they should be brought to book."
Bulk text messages have been outlawed for 15 days, senior civil servant R.K. Singh announced, with telecom operators ordered to immediately block messages sent to more than five people at a time.
Police in Bangalore, aided by security specialists, have been working to find the sources of the anonymous messages spread via text messages, Facebook and online message boards.
They say that no attacks on northeastern migrants, who number about 240,000 in Bangalore, have been reported.
An official in the western Indian city of Pune also said some migrant workers were heading back to the northeast due to fears of assault.
"We estimate that between 600 to 700 people, mostly labourers, have left Pune to go back home to the northeast region in the past three days," said Pune railway police spokesman Y.K. Singh.
"It is likely that another 250 to 300 could leave today (Friday)," he told AFP.
In Assam's main city Guwahati, Assamese migrants, who are physically distinct from most other Indians and look more East Asian or Tibetan, were also arriving from the city of Hyderabad and from Kerala state.
Arun Jaitley, an opposition Bharatiya Janata Party (BJP) leader, said lawmakers must accept there was "an onerous responsibility on each of us to make sure that this panic situation comes to an end".
For the second night in a row, thousands of northeasterners on Thursday had boarded trains in Bangalore for Guwahati.
"We had to arrange at short notice two special trains of 20 coaches each to Guwahati to clear the extra rush of passengers and attach five more coaches to the two daily trains," South Western Railway spokesman Suvankar Biswas told AFP.